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Swapping soft drinks for tea can save your child’s teeth

Extractions are now the most common reason for children aged between five and nine to be admitted to hospital.

However new research has identified a simple solution which not only protects against decay but also reduces the risk of obesity and diabetes. “We should turn back the clock and encourage children to drink more tea,” says the scientist behind it, Professor Robin Seymour, emeritus professor of restorative dentistry at Newcastle University and an adviser to the Tea Advisory Panel.

He explains: “We have come to think of tea as an adult drink but until relatively recently even very young children enjoyed tea on a regular basis. Historic data shows that in the 1950s more that half of all four-year-olds drank tea which is far more tooth-friendly than the fizzy drinks, squash or juice they often drink today.”

Studies confirm children get most of their free sugars, which are the most damaging, from soft drinks. An average 500ml bottle of Coca-Cola has 13.5 cubes of sugar, which is more than twice the recommended daily maximum for a child aged seven to 10.

Even supposedly healthier options, such as orange juice and blackcurrant squash, have about 7.5 cubes of sugar in a 300ml serving; 50 per cent more than the upper limit recommended for four to six-year-olds.

Professor Nigel Hunt, who heads the faculty of dental surgery at the Royal College of Surgeons, says: “The sweet habits of our children are having a devastating effect on their teeth. That children as young as one or two need to have teeth extracted is shocking. It’s almost certain the majority of these extractions will be down to tooth decay caused by too much sugar.”

Swapping soft drinks for tea would slash sugar consumption but Professor Seymour’s study, which has just been published in the journal Oral Health, shows that is not the only reason why tea is good for our teeth.

Fizzy drink


Children get most of their free sugars, which are the most damaging, from soft drinks

Tea is also rich in natural fluoride and among adults it provides about 70 per cent of the recommended daily intake. Unlike the fluoride in toothpaste, because the fluoride in tea is absorbed, it also begins strengthening teeth before they emerge, making it beneficial for younger children.

Professor Seymour’s study adds: “Fluoride also has benefits for bones, since at low doses it can embed in the bone matrix protecting against erosion, resulting in increased density and hardness.”

In addition to fluoride, tea also contains polyphenols with antibacterial activity which help combat bacteria associated with cavities, gum disease and bad breath. These polyphenols also suppress production of acids which contribute to erosion of dental enamel and cavities.

Concerns have been raised about the potential dangers of getting an excess of fluoride from tea but Professor Seymour says: “These are not borne out by evidence.”


Among adults flouride in tea provides about 70 per cent of the recommended daily intake

A study which suggested economy brands contained high levels had used twice the amount of tea routinely used to make a cuppa and some samples were left to “brew” for as long as 30 minutes.

European regulators have set the safe upper limit for children at 0.1mg per kilogram of bodyweight, which is one or two cups for children aged four to 10 and about four cups a day for older children.

Dr Tim Bond, an expert member of the Tea Advisory Panel, says: “Tea fell out of favour as a drink for children because of unfounded concerns around caffeine, yet many parents happily give their children cola which contains caffeine alongside large amounts of sugar.

“It doesn’t make sense. This new research confirms it is not only safe to give children unsweetened tea, it is a lot healthier than many of the drinks they are downing now.”

He adds: “Tea has an array of healthy micronutrients such as fluoride, manganese, zinc and some B vitamins but it’s the polyphenols in tea which are of enormous interest. Tea polyphenols are the biggest source of antioxidants in the British diet and they have proven antioxidant and anti-inflammatory properties. A number of studies have linked tea polyphenols with a reduced risk of diabetes, cardiovascular disease and obesity.” 5, 2017


Use Fluoride Nilogon to have fluoride-free water


Chandan Kumar Duarah


Dengaon is a beautiful area consists green hills, plains and rivers in Brahmaputra valley. More than 50 villages and most of its inhabitants are belong to Karbi tribe. This area in border of Nagoan and Karbi Anglong districts in Assam are highly and dangerously fluoride-affected in Brahmaputra valley.

I have visited fluoride-affected villages in Nagaon- Karbi Anglong districts in Assam along with Dr. R K Dutta, a chemical scientist working in Tezpur University. We went to many families and encountered with their members some are suffering from fluorosis and some families are trying to to get rid of the demon. We delivered suggestions and demonstrated few easy methods to have fluoride-free water.

The presence of excess amount of fluorine was tested in the water from rivers, ponds, wells, tube-well and deep-wells. Villagers have been suffering from fluoride for centuries which was detected in last decade. There are no drinking water supply facilities in remote villages which are not easily accessible. Symptoms of excess fluoride induced disorders are prevalent some states of the country including Brahmaputra valley. Karbi Anglong and Hojai districts are the most fluoride-affected districts in Assam.

Flouride has been an invisible enemy contains in drinking water as chemical contaminant mostly in ground water in Brahmaputra valley. It has been a matter of grave concern that almost all districts in Assam are fluoride and arsenic affected. Villagers from different tribes and communities have been witnessing this demon with dental and skeletal flourosis. A small amount of fluoride is good for health but excess fluoride of drinking water causes various health problems including damage of tooth and bone. Fluoride is a deadly poison. A long term ingestion of fluoride in drinking water and cooking water causes to other health problems. Affected villagers had no option to minimise the presence of fluoride and only some families use to drink filtered water. Moreover, general filter cannot remove or minimise fluoride.

Fortunately villagers have found a new low-cost technology to remove fluoride and iron from water recently. Now villagers are using this fluoride removal family and community unit to have fluoride-free water. Villagers have installed fluoride Nilogon – a low-cost and simple method for removal of fluoride from contaminated groundwater. Fluoride Nilogon is a method for removal of excess fluoride from contaminated groundwater for drinking purpose through phosphoric acid and crushed limestone treatment based on precipitation-absorption developed by a team of researchers led by Dr R K Dutta. The name was coined from fluoride and Nilogon is an Assamese equivalent of ‘removal’ in English.

The method removes fluoride efficiently and selectively without leaving any toxic residual in the water at a recurring cost of ₹ 1 per 100 litre of water. The Fluoride Nilogon system can be custom designed to meet the requirements of the users ranging from small household to community. It uses a crushed limestone fixed-bed reactor where the water is treated for 3 hours in presence of a small quantity (0.00067 M) of phosphoric acid.

For small communities like school a 200 or 500 litre plastic drum can be used as the reactor and another 200 litre drum can be used as the sand gravel filter. After filling with crushed limestone, a 200 liter drum can be hold about 88 litre and a 500 litre drum can hold about 220 litre of water. The filter shuold have a 15-20 cm layer of small 2-3 cm size gravels, at the bottom, covered by a thin porous cloth, above which, there should be a 50-60 cm thick layer of clean medium size sand. People have been collecting water from a community unit set up near Dengaon Higher Secondary School for a year which was set up experimentally first.

After long sufferings and government negligence people of some villages of Dengaon region in Karbi Anglong districts have choosed to use “Flouride Nilogon” unit to get flouride-free water. “In Flouride Nilogon, the flouride containing water, mixed with a small quantity of phosphoric acid, is put into a crushed limestone bed plug-flow reactor and kept for a residence time of at least three hour. Flouride is removed in the reactor. The water is filtered using a sand-gravel filter after three hours” – Dr R K Dutta said.

The Fluoride Nilogon method has been developed by a group of researchers lead by Dr. Dutta. He is a professor in the Department of Chemical Sciences, Tezpur University. Flouride Nilogon removes the excess fluoride retaining only a small amount of fluoride (0.7 ppm) require for a good health. The treatment water does not contain any residual chemical added from outside. Its pH is about 7.5 which is very safe for drinking. However, the treated water should be consumed only after boiling.

Families can use a Flouride Nilogon unit with arrangement of minimum two big size buckets as water from upper bucket can come to lower bucket using a tap. It must be sure that the tap of the upper 40 liter bucket which contain crushed limestone container is closed. 15 liter of water is added in the bucket. Then 7 ml of the dilute phosphoric acid solution be added to it and mix. Then the amount of acid solution mixed water be poured in the first bucket containing crushed limestone and leave it for at least three hours. In a 30 liter crushed limestone bucket, 11 liter water can be treated and and 55.2 ml phosphoric acid has to be added. There is no harm if you leave it like that for longer time even for a day. Flouride is removed here along with neutralisation of the acid. Now water can be filtered using the sand gravel filter in second lower bucket.

A household unit used by common people consists of a plastic bucket of 40 litre capacity for the reactor and another 20 litre bucket for the sand-gravel filter. Both buckets are fitted with a plastic tap each towards the bottom. The 40 litre treatment bucket is kept at a level above the filter. The 40 litre bucket is filled with crushed limestone of 0.1 to 1.5 cm size. This limestone-filled bucket can hold about 15 litre of water. The filter should have an 8-10 cm thick layer of small 2-3 cm size gravel layer at the bottom. The rest of the bucket should be thin porous cloth between the sand and the gravel layer to stop sand from going to the gravel layer.

Families from Dengaon area acknowledged benefits of Fluoride Nilogon to get fluoride-free water. Some people are using water from community set up and some have installed their own set up inside their house. The solution used in the method is a dilute solution (8.5%) of an acid even though it is a weak acid, it shoul be kept carefully. It should be kept away from children. with water in case of its contact with hand, skin or eye.

It is a simple efficient and low-cost method of removing excess fluoride from water. It this method crushed limestone is used along with a very small amount of a solution of a weak acid called phosphoric acid. The use of phosphoric acid in water purification is safe. Phosphoric acid is used in packaged food and soft drinks like Pepsi, Prof. Dutta said.

Thanks to Jibon Patar, a local teacher in Dengaon has been extending helps and workin with issues for years .

Researcher from Assam Leads Black Hole Research In MIT


The last meal that the supermassive black hole of the Milky Way had was six million years ago, when it consumed a large clump of infalling gas before burping out a colossal bubble of gas weighing the equivalent of millions of suns, a new research led by an Indian scientist from here has found.

With the help of the NASA’s Hubble Space telescope, Rongmon Bordoloi and his team of researchers from the Massachusetts Institute of Technology in Cambridge found that several distant quasars can be seen through the northern half of the Fermi Bubbles, an outflow of gas expelled by the Milky Way galaxy’s hefty black hole.

The Hubble Space Telescope probed the quasars’ light for information on the speed of the gas and whether the gas is moving toward or away from Earth. Based on the material’s speed, the research team estimated that the bubbles formed from an energetic event between 6 million and 9 million years ago.
“Six-nine million years might sound like a long time in human years. But in terms of cosmic timescale, it is like the blink of an eye. Just to give you the scale, the universe is approximately 13.7 billion years old, and the dinosaurs became extinct around 66 million years ago. So the last meal that the supermassive black hole of the Milky Way had was after the dinosaurs became extinct,” says Bordoloi.

“For the first time, we have traced the motion of cool gas throughout one of the bubbles, which allowed us to map the velocity of the gas and calculate when the bubbles formed,” he says.

“It was a very strong and energetic event. It may have been a cloud of gas flowing into the black hole, which fired off jets of matter, forming the twin lobes of hot gas seen in X-ray and gamma-ray observations. Ever since then, the black hole has just been eating snacks,” he says.

A black hole is a dense, compact region of space with a gravitational field so intense that neither matter nor light can escape. The supermassive black hole at the centre of our galaxy has compressed the mass of 4.5 million sun-like stars into a very small region of space.

Asked when the next meal would be, Bordoloi told PTI, “Recently a binary star called G2 (with a mass of several earth masses) came very close to falling into the supermassive black hole at the centre of the Milky Way. Somehow it didn’t fall through and survived.’

“There was some increased activity in terms of X-ray flares which could be due to a change in the strength of winds from nearby massive stars that are feeding material to the black hole. But in short, we don’t know when the next big meal would be. There are stars orbiting the galactic centre, and if they fall into the black hole at some point, we might see a good light show.”

What the snacks consisted of is somewhat unclear.

“It could be a gas cloud falling in or even some stars orbiting near the galactic centre that fell in,” says Bordoloi, who has been using NASA facilities like the Hubble Space telescope since his graduate school years.

According to him, the kind of gas flow observed is called a nuclear outflow.

“Such outflows are important regulatory mechanisms in the life cycle of a galaxy that controls that gas reservoir of a galaxy. If such outflows are too vigorous, it would mean that all the gas inside a galaxy would be kicked out and that would mean no new star-formation in the galaxy would occur.

“By studying the flow of gas into and out of the galaxy, we can study the fate of the Milky Way. We can start to predict if it will keep forming stars (currently there is almost one new star born in the Milky Way every year), or whether it will run out of gas supply and become an old and dead galaxy,” he says.

On the challenges ahead, he says, “One big challenge is to actually see which theoretical predictions can explain the observations we see here. It is always fun to push our understanding of a subject by comparing the models with observation.

“Moreover, we are conducting new Hubble observations in this field, and hopefully they would also show some new surprising results.”
Tags: research, nasa, hubble space telescope, galaxy, space


New light on dark matter

Dark matter is as mysterious as it sounds – very little is known about it, save that it makes up about 85 per cent of all the matter in the universe. Now, German and Hungarian scientists have thrown some light on a type of dark matter particle that has been postulated, known as the axion. They have established that axions can have a mass between 50 and 1500 micro electron volts, making them some ten billion times lighter than the electron. This computation has been published in the journal Nature. An interesting fact is that these calculations were done numerically using a (Bluegen/Q) super computer, JuQueen, housed in the Julich Supercomputer Centre in Germany.

Dark matter is so known because it interacts weakly with matter and so is notoriously difficult to detect. Yet, indirect proof of its existence comes from observation of rapidly rotating galaxies, which cannot be held together merely by the gravitational pull of the matter they contain – there has to be a lot of invisible stuff known as “dark matter” to prevent them from flying apart with the force of their own energies. Such inferences imply that nearly 85 per cent of the universe is made of dark matter, the known matter only contributes 15 per cent.

Several candidate particles have been postulated that may constitute dark matter – both highly massive and lightweight – but none of the experiments have detected any such particle so far, directly. Axions are particles proposed by extending quantum chromodynamics (QCD) the theory that describes “strong interactions,” the way quarks and gluons bond to form matter particles such as protons, neutrons etc. Though they have been proposed and there are experiments to study them (for instance, the Axion Dark Matter Experiment, ADMX), there has been no real handle on these until now. The present work sets a mass bound on the axions, between 50 and 1500 micro electron volts, as mentioned earlier. This would require that there exist ten million such particles for every cubic centimetre of the universe. Also, because dark matter is not evenly spread out, but occurs in clumps, there should be nearly a trillion axions per cubic centimetre in the Milky Way – our galaxy.

Knowing the expected mass range of the axion not only gives a better understanding of the particle itself, but also can serve as a guideline for doing experiments. Instead of firing in the dark, ADMX, for instance, now has a definite range to study keenly.

Subashree Desikan

Brahmaputra – The Beautiful River or The Battleground?

Bogibeel, the fourth bridge on Brahmaputra is under construction between Dhemaji and Dibrugarh district.  Photo – Parag Jyoti Saikia

Capture 3

The Brahmaputra River, geologically is the youngest among the major rivers in the world yet it is known as a moving ocean. The river Brahmaputra travels 2880 km from its origin in the young Himalayan range through the Tibet and India and finally merges with the sea in Bangladesh by opening its streams like the roots of a large Banyan tree. While traversing through India the river is astonishingly wide at some areas. In Upper Assam near Dibrugarh the river is 16 km wide where as in lower Assam at Pandu, near Guwahati the river is 1.2 km wide but in the immediate downstream it is nearly 18 km wide. Brahmaputra which is mainly a glacier fed river has also the distinction of being the river with highest sediment yield 852.4 t/km2/y in the world and second highest water yield at delta, next only to Amazon.[1]

Origin and Path

The BrahmaputraRiver originates in the Chemayungdung mountain ranges which nearly sixty miles south-east of Mansarovar lake in the MountKailash range in Southern Tibet at an elevation of 5300 m.A spring called Tamchok Khambab spills from the glaciers which later gather breath and volume to become the Tsangpo, the highest river in world.

A Buddhist shrine called a stupa overlooks the Brahmaputra River in southern Tibet. Source:

Out of its total length of 2,880 km the Brahmaputra covers a major part of its journey in Tibet as Tsangpo. Tsangpo or the BrahmaputraRiver flows 1625 km in Tibet parallel to the main range of Himalayas before entering India through Arunachal Pradesh.

Apart from the name Tsangpo, the Brahmaputra is also known by its Chinese name, Yarlung Zangbo in Tibet.  There are several tributaries of Tsangpo in Tibet. According to Encyclopedia Britannica,  Raka Zangbo (Raka Tsangpo), Lhasa (Kyi) and Nyang Qu (Gyamda) are prominent north bank tributaries where as Nyang Qu (Nyang Chu) is a tributary on the south bank. The Raka Zangbo (Raka Tsangpo) joins Tsangpo in the west of Xigazê (Shigatse) and Nyang Qu (Gyamda) River joins the river from the north at Zela (Tsela Dzong). The Lhasa (Kyi) river flows past the Tibetan capital of Lhasa and joins the Tsangpo at Qüxü.  The right bank tributary Nyang Qu (Nyang Chu) meets the Tsangpo at Xigazê.

Before entering India, the river passes Pi (Pe) in Tibet and suddenly turns to the north and northeast and cuts a course through a succession of great narrow gorges between the mountain Gyala Peri and Namjabarwa (Namcha Barwa) in a series of rapids and cascades.

The Great Bend of Tsangpo where China planning to build world’s biggest hydropower project Source:

The river then turns south and southwest and flows through a deep gorge across the eastern extremity of the Himalayas with canyon walls that extends upward for 16,500 feet (5,000 meters) and more on each side. This is the celebrated great bend where China has plans to build the world’s biggest hydropower project of 40 000 MW capacity and also divert water from here to the North China, though China is currently denying any such plans.

Siang River Source:

The river enters Arunachal Pradesh near Gelling where it is known as the Siang or Dihang. The total length of Siang River is 294.5 km till its point  of confluence  with Dibang and Lohit River. The elevation of Siang river catchment area ranges from 90 m to around 5800 m. In India the total catchment of Siang river up to its confluence with Dibang is 14965.30 sq km.[2]

The SiangRiver meets two other major tributaries of Brahmaputra, Dibang and Lohit in the west of Sadiya, at a place named Kobo. From this confluence point, the river is known as the Brahmaputra till it enters Bangladesh. In India the journey of the river Brahmaputra is 918 km long.

A recent study has shown that Kobo used to be confluence point in 1915.  By 1975 the confluence shifted to a place called Laikaghat which is 16 km downstream of the earlier point of confluence. In 2005 through satellite images it was observed that the confluence point has shifted “19 km farther downstream”.[3]

The river crosses Assam below Dhubri and enters Bangladesh where the river is known as Jamuna and it flows for 337 km. Regarding Brahmaputra’s role in Bangladesh a study writes “The Jamuna is the local name given to the river for its entire length in Bangladesh to the Ganges junction.

Jamuna River in Bangladesh Source:

The Brahmaputra-Jamuna has one principal tributary input, the TeestaRiver in the north-west, and two major offtakes on the left bank that are the Old Brahmaputra and the Dhaleswari. The Brahmaputra/Jamuna River contributes ~51% of the water discharge and 38% of the sediment yield to the Padma (Schumm and Winkley, 1994), with the sediment yield being estimated at 590 MT/ yr and the sand fraction contributing 34% of this total (Sarker, 1996).”[4] The Jamuna joins the Ganges at Goalundo Ghat and from here the combined flows of these two mighty rivers are known as Padma which joins Meghna in the downstream. The united stream thereafter known as the Meghna and with this name the river Brahmaputra ends its journey, entering the Bay of Bengal.

Bhutan forms an integral part of the Brahmaputra river basin even though it does not come in the path of the river. In our subsequent blogs we will bring a detail account of Bhutan’s role in Brahmaputra river basin.

 The Brahmaputra River Basin

The Brahmaputra river is an international river and its river basin is spread over four countries Bhutan, Tibet , India and Bangladesh with a total basin area of 5,80,000 sq. km. Out of this total catchment area 50.5% lies in Tibet, 33.6% in India, 8.1% in Bangladesh and 7.8% in Bhutan. For geologist and environmentalist the Brahmaputra is a very unique river because “drains such diverse environments as the cold dry plateau of Tibet, the rain-drenched Himalayan slopes, the landlocked alluvial plains of Assam and the vast deltaic lowlands of Bangladesh.”[5]

Map of Brahmaputra Basin from its origin to its confluence Source:

In India the total basin area of BrahmaputraRiver is 197 316 sq. km. which 5.9% of the total geographic area of the country. In India the river is spread over states of Arunachal Pradesh, Assam, West Bengal, Meghalaya, Nagaland and Sikkim.

In India state-wise the drainage area of the BrahmaputraRiver is as follows:


Drainage area (sq. km)

% of state area in Brahmaputra basin

Arunachal Pradesh 83 740 100%
Assam 71 216 90.79%
West Bengal 12 585 14.18%
Meghalaya 11 780 52.52%
Nagaland 10 895 65.71%
Sikkim 7 100 100%
Total 197 316

Source: ‘Intregrated Water Resource Development: A Plan for Action’, MoWR, Govt. of India, September, 1999

The Arunachal Pradesh and Nagaland portion of the Brahmaputra river basin is mainly covered by mountain ranges and narrow valleys. Meghalaya part of the basin is majorly covered by hills where as Assam and West Bengal are mostly plain areas.

Politically in India the basin is spread over 22 parliamentary constituencies (2009) comprising 12 in Assam, 4 in West Bengal, 2 in Arunachal Pradesh, 2 in Meghalaya, 1 in Sikkim and 1 in Nagaland.

Projected Water Use for Diverse Purposes in the Brahmaputra Basin

Catchment Area 197 316 km2
Population (1991 census) 29.1 million
Surface-Water Potential (Av Annual) 629 km3/year
Utilisable Surface Water 24 km3/year
Total Replenishable Ground Water (Av. Annual) 26.55 km3/year
Natural Groundwater Recharge from Rainfall 25.72 km3/year
Estimated Utilisable Flow excluding Ground Water 21 km3/year

Source: ‘Integrated Water Resource Development: A Plan for Action’, MoWR, Govt. of India, September, 1999

Tributaries of Brahmaputra

Sub-basin map of Siang River Source: Environment Assessment Report Siang Basin In Arunachal Pradesh, Interim Report June 2012

Studies have stated that the Brahmaputra river in its entire course receive water from a large number of tributaries. A study called “Study of Brahmaputra River Erosion and Its Control” done by IIT Roorkee[6] stated “the Brahmaputra receives as many as 22 major tributaries in Tibet, 33 in India and three in Bangladesh.” However this study did not mention anything about the river in Arunachal. We have already mentioned about the few of the tributaries Tibet. In Arunachal the major tributaries of Siang River are Ringong Asi, Yang Sang Chhu, Sigong/ Sirapateng, Niyikgong, Angong, Simang, Yamne, Siyom, Yargyap, Hirit Korong.[7]

In the course of journey through Assam from east to west, some of the important tributaries of the BrahmaputraRiver which join the river on the north bank are Lohit, Dibang, Subansiri, Jiabharali, Barnadi, Puthimari, Pagladia, Beki, Manas, Ai, Gabhoru, Chompawati, Sankosh, Raidhak, Torsa, Teesta etc. Burhidihing, Desang, Dikhow, Jamji, Bhogdoi, Kakdonga, Dhansiri, Kopili, Kolong, Sonai, Digaru, Bharalu, Krishnai, Dudhnoi are the major tributaries on the left bank. The actual number of rivers and rivulets which joins the mighty river is much larger than this list. In subsequent blogs we will try to go into details of some of the tributaries of the river Brahmaputra.

Hydrology of Brahmaputra

For the river Brahmaputra the average annual flow (water discharge) throughout Assam vary from 8500 to 17000 cubic meters per second. At Pandu Ghat near SaraighatBridge the average annual floods recorded was 16,000 cubic meters per second. During floods water discharge reaches its peak and the yearly average peak flow recorded was approximately 51,000 cubic meters per second.[8] At its mouth in Bangladesh, the average annual discharge of the river is 19,830 cubic meters per second. This is the fourth highest average annual discharge in the world. For the river Brahmaputra the highest daily discharge was recorded in August 1962 at Pandu which was 72,726 cubic meters per second. The lowest daily discharge at the same place was 1757 cubic meters per second in February 1968.[9]

Satellite image of the river Brahmaputra (2008) just downstream of Guwahati city indicating intense braiding. width of the river at pandu is 1.2 km but donstream is about 18km. Source: ‘Riverbank erosion: a perspective” a presentation by Dr. Bipul Talukdar, Assam Engineering College

Though the Brahmaputra has been described as a braided river, recent studies have shown that the river does not fit into the conventional definition of braided river. A recent study states “In the study reach of the upper Assam area, the Brahmaputra appears to be a multichannel and multi-pattern river that has a tendency to very frequently generate ananabranching[10] (Latrubesse, 2008) pattern in decadal scale.” [11]

The Brahmaputra has been widening its (riverbed) size continuously from the last century. Reports from Water Resource Department showed that in Assam the river Brahmaputra was spread over for 4000 sq km in 1920 but in 2008 this has increased to 6000 sq km.[12]

The Brahmaputra along with several of its major tributaries like Subansiri, Jia Bharali, Manas had very high water yields[13]  which are higher than most of the major rivers in the world. The reason behind such high water yield for Dr. D.C. Goswami, one of the renowned environmental scientist from Assam is “High monsoon rainfall in the upper catchments and their steep gradients are considered to be the major factors responsible for the high rates of unit discharge which in turn help generate the high sediment yield from the basin and contribute significantly towards causing drainage congestion in the valley.”[14]

Seismicity and Brahmaputra Basin

The Brahmaputra river basin and its adjoining hill ranges are seismically very unstable because it is located in the Eurasian (Chinese) and Indian tectonic plates. The most severe earthquakes with Richter magnitude 8.7 was recorded twice in the valley, in 1897 and 1950. The latter one particularly had severe impacts on the river Brahmaputra. As a result of this earthquake river bed was raised at least by three meters at Dibrugarh which had increased the flood and erosion intensity of the river. In the opinion of geomorphologists “the region’s active seismicity has a significant impact on the hydro-geomorphic regime of the Brahmaputra system of rivers, causing landslides that result in the natural damming of rivers, flash floods due to the bursting of landslide-induced temporary dams, raising of riverbeds by siltation, fissuring and sand venting, elevation of existing river and lake bottoms and margins, creation of new water bodies and waterfalls due to faulting.”[15]

Climate Regime

The Brahmaputra in its path from snow covered mountains of Himalaya to the deltaic flood plains of Bangladesh covers different climatic regimes. The mean annual rainfall in the Brahmaputra basin excluding the Tibetan portion is 2300 mm.  The distribution of rainfall is different at different parts of the basin. In the southern slopes of Himalaya the rainfall is over 6000 mm but in parts of Nagaland this is 1200 mm. The monsoon rainfall (June to September) contribute 60-70% to the annual rainfall of the basin.[16]

In this basin, areas which are above or equal to the elevation of 1500 m experience snowfall. In the Indian part of Brahmaputra basin there are 610 glaciers which covers an area of 928.91 sq km and the volume of these glaciers are 49.57 cubic km. Out of these 449 glaciers are in Teesta basin and 161 glaciers are in Arunachal.[17]  In the Brahmaputra basin, Himalayan snow and glacial melt waters play a very significant role in water availability and climate change will have severe impacts on this. Climate change will also impact the rainfall and snowfall pattern in the Brahmaputra basin. This issue needs more serious attention and we will come up with more detailed blogs on this.

Bio-Diversity in the Brahmaputra Basin

The Lohit flooplains, immediately dowsntream of Lower Demwe HEP, constitute an Important Bird Area as per international criteria and is also a potential Ramsar site Photo: Neeraj Vagholikar

The Brahmaputra river basin hosts very rich and unique bio-diversity. The whole of northeastern region is a globally recognized bio-diversity hot spot.  In the Indian territory the total forest cover of the Brahmaputra basin is 1,14,894 sq. km. which is 54% of the total basin area. In the distribution of forest cover among 6 states in Brahmaputra basin, Arunachal Pradesh tops the list with 82.8% forest cover but it is sad that the highest number of hydro-electric dams are planned in this state inviting disastrous impacts for the biodiversity, forests, people and environment. The tally of rest of the five states is as follows – Nagaland (68.9%), Meghalaya (63.5%), Sikkim (38.1%), West Bengal (21.4 %) and Assam (20.6 %).

Besides, the aquatic bio-diversity of the Brahmaputra and its tributaries is also very rich. Here we should also take the case of ‘beel’ or wetlands in the Brahmaputra flood plains which according to experts work as ”ecotonal zones” and ”play an important role in the dynamics of the Brahmaputra ecosystem, as these are natural feeding and breeding grounds for a number of fish species and other aquatic fauna.”[18]

Flood and Erosion

Brahmaputra river basin is known to be very prone to flood and erosion and these two hazards have led to many problems in the basin. In India, out of the eight northeastern states, Assam faces the most severe brunt of flood and erosion. Both flood erosion has been severely affecting the economy as well political, social and cultural milieu of Assam.

Experts opine that natural as well anthropogenic factors lead to devastating floods in northeastern region. “The unique geo-environmental  setting of the region vis-à-vis the eastern Himalayas, the highly potent monsoon regime, weak geological formation, active seismicity, accelerated erosion, rapid channel  aggradations, massive deforestation, intense land use pressure and high population growth especially in the floodplain belt, and ad hoc type temporary flood control measures are some of the dominant factors that cause and/or intensify floods in the Brahmaputra and the Barak basins (Goswami, 1998).”[19] The Brahmaputra river basin is also prone to flash floods and some of the worst flash floods have occurred in the valley in the new millennium.

Along with floods, erosion is also threatening the lives of the people in the state of Assam as it leads to permanent loss of land.  Here we can take the case of the river island Majuli, which had been one of the worst sufferers of the erosion done by Brahmaputra. In 1853 the total area of Majuli was 1129 sq km but it has now reduced to 3.55 sq km.[20]

Ilish fishing, Dauladia, Bangladesh, 2001 Source:

In Bangladesh the Brahmaputra river which known as Jamuna is also infamous for severe floods and erosion. The river carries huge water and sediment discharge in this deltaic region. Because of its geographical setting, Bangladesh is very much dependent on its river for fertile fields and diverse flora and aqua culture but rivers also brings several hazards in the form of floods and erosion. Bangladesh has witnessed severe annual floods but the floods in 1987, 1988, 1998 and 2004 were the most severe ones in recent decades. But studies have shown that, “The people of Bangladesh have adapted their lifestyle for centuries to live with river flooding – frequently moving their temporary bank-side homes, planting on newly emergent river bars, and sometimes raising their homesteads above water level in flood periods (Paul, 1997). However, a growing population, coupled with the expansion of infrastructure and economic development, has resulted in an increase in the intensity of flood damage (FPCO, 1995; Paul, 1997; CPD, 2004). The lives of many millions of Bangladeshi citizens is thus reliant on these rivers, with up to 600,000 people living on the riverine islands and bars alone (Sarker et al., 2003).”[21]

In order to protect people from the fury of floods and erosion the main measure taken in India as well in Bangladesh is the construction of embankments. In Assam the total length of embankment is 4,473.83 km constructed on a total of 130 small and big rivers. But recent reports say that out this, 3376 km embankments are in a vulnerable condition and need immediate strengthening and repair.[22] As a deltaic region Bangladesh too has put its thrust on increasing length of embankments. In 1989 Bangladesh launched an elaborate flood control programme through construction of embankments which was named as ‘Flood Action Plan’. But this plan was vehemently criticized both at national and international level.

Protest against big dams – KMSS (Krishak Mukti Sangram Samiti) members protesting in Pandu Ghat in Guwahati against the ship carrying the turbines for the Lower Subansiri project. Source:

In order to control the floods in Brahmaputra valley one of the proposed solution is construction of multi-purpose dams. In fact flood control was one of the pretexts for hydro-development in the northeastern region. But the idea that multipurpose dams can lead to flood control along with hydro-power generation is actually contradictory and unviable as seen from experience of such projects. Studies done on some of the biggest multi-purpose river valley projects of independent India, e.g. ‘Unravelling Bhakra’ by Shripad Dharmadhikary, ‘Drown and Dammed’ done on Hirakud by Prof Rohan D’Souza, “One Valley and a Thousand: Dams, Nationalism, and Development, Studies in Social Ecology & Environmental History” on Damodar Valley dams by Daniel Klingensmith have shown how unviable this proposition is. A number of these dams have actually created avoidable flood disasters in the downstream areas due to wrong operation of the dams[23]. In case of the mightly Brahmaputra river, this is likely to prove even greater disastrous considering its characteristics described above.

Today Brahmaputra valley is witnessing severe opposition against hydro-power dams.  The struggle against the Lower Subansiri hydro-electric project can be regarded as milestone. In the Brahmaputra valley the hydropower projects have been opposed also because of the impacts which it will going to have in the downstream as well as on the biodiversity, seismicity, society and culture of one of the most ecological sensitive areas. .

Institutional Mechanism over Brahmaputra in India

The Brahmaputra Board is the foremost body on Brahmaputra established by Government of India under an Act of Parliament i.e. The Brahmaputra Board Act, 1980 (46 of 1980) under the Ministry of Irrigation which now renamed as Ministry of Water Resources. The main task entrusted on Brahmaputra Board is ‘planning and integrated implementation of measures for the control of floods and bank erosion in the BrahmaputraValley and for matters connected therewith.’ Both Brahmaputra and Barak valleys are under the jurisdiction of Brahmaputra Board. Even though this independent board was established to better manage the flood and erosion problem of the two river basins, but its activities have come under severe public criticism. Besides Brahmaputra Board, the State Water Resource Department and Central Water Commission also looks after water issues in the river basin. Recently international funding agency Asian Development Bank (ADB) has come to be associated with flood and erosion control in the Assam but from the experiences of Bangladesh, the advent such agencies must be dealt with precaution.

Brahmaputra Valley as the Point of Confluence for People and Cultures

The Brahmaputra is a dynamic river whose dynamism is not only limited to its physical characters or features of the river, but immersed in social, political, economic and cultural aspects. The Brahmaputra valley has been the space of assimilation for people from different races and the one can find large variety of languages and dialects being spoken in this valley. The northeastern region falls under the Brahmaputra and Barak River basin[24] which is home for more than 166 separate tribes, 160 scheduled tribes and over 400 other tribal and sub-tribal communities and groups, speaking a wide range of languages (Climate Change in India: A 4×4 Assessment, 2010). The northeastern region can also be considered as an ‘ethnological transition zone’ between India and the neighbouring countries of Bhutan, Tibet, Burma and Bangladesh. In this region one can find 220 languages belonging to three language families – Indo-Aryan, Sino-Tibetan and Austric.[25]

Relevance of Brahmaputra for Assam

For Assam, the state located at the center of the northeastern region, the river Brahmaputra paves its way through this state like the lifeline of the state. The river ‘Brahmaputra’ literally means ‘Son of Brahma’. It is also one of the few rivers in India which is regarded as a ‘male’ river. There are several myths and legends about the Brahmaputra’s origin and we will bring those together in our coming blogs.

Bogibeel, the fourth bridge on Brahmaputra is under construction between Dhemaji and Dibrugarh district. Photo – Parag Jyoti Saikia

In Assam Brahmaputra River is also known by several other names  i.e. ‘Luit’, ‘Siri Luit’, ‘Bor Luit’ ‘Bor Noi’. For the people of Assam, the Brahmaputra is a symbol of great pride due to its ‘moving ocean’ size but this also ignites fear when it rises to its strength during floods. People of Assam have faced difficult times when the river has come to its full strength. Famous singer Jayanta Hazarika wrote, when he formed ‘Xur bahini’ to gather relief for flood victims “Luitor Bolia baan, toloi koloi nu dhapoli meliso, hir hir sowode kal roop dhori loi kaak nu bare bare khediso (Oh the maddening floods of Luit, where are you heading this time. Whom are you chasing again with frightening sound of your waves)”.

But this river is also the source of strength for the people of Assam. Time and again, they have expressed their unity as ‘Luitporia’ or ‘people from the banks of Luit’. The famous cultural icon of Assam, Jyoti Prasad Agarwala wrote in 1942 during Indian Freedom movement “Luitor parore ami deka lora, moriboloi bhoi nai (we are the youth from the banks of Luit and we don’t have any fear of death)”.  For another legendary cultural icon, Dr. Bhupen Hazarika  who is known as the bard of Brahmaputra, the river’s power of destruction was the source which will awaken the people. In his famous song “Bistirno parore” he asked the river – “Sahasro barishar, unmadonar, avigyotare, pangu manobok sawal songrami aru agrogami kori nutula kiyo (with your maddening experience of thousand monsoons, why don’t you arouse the disabled human beings for struggle and progress)”.

This blog is a small step to document the various aspects of the river Brahmaputra. It is the need of the hour since a flood of dams are proposed to submerge the Brahmaputra valley. Chinese plans of dam construction is not very much in the public domain but the impacts of dam construction of in the upstream Tibet will have severe impacts on the Brahmaputra river. Besides, the bogey of Chinese threat to divert the waters of Siang is used by the Indian government to push for rapid dam construction sidelining all the social, environmental, safety, sustainability, climate change concerns and impacts on the river ecosystem. The government very shamelessly has also put aside all the democratic processes to push for rapid dam construction. Though there is no proposal for a dam on the Brahmaputra in Assam, there are proposals to dam its major upstream tributaries.  This upsurge of dams, if they do get constructed will have huge impacts on the Brahmaputra River which are yet not known due to lack of credible projects specific or cumulative impacts assessment studies. These studies should include issues like  the river ecosystem, river bio-diversity, forests and wildlife, climate change, floods and erosion and economic and socio-cultural impacts. However, we are hopeful that the ongoing struggles against such unjustifiable projects will succeed and all these projects won’t come up. Through a series of blogs we will also try to bring together all these different streams of concerns.

Himanshu Thakkar, Parag Jyoti Saikia

South Asia Network on Dams, Rivers & People (

[1] Lahiri, S.K., Sinha, R., Tectonic controls on the morphodynamics of the Brahmaputra River system in the upper As-sam valley, India, Geomorphology (2012)

[2]EnvironmentAssessmentReport  SiangBasin In Arunachal Pradesh, Interim Report June 2012, Prepared for Central Water Commission(CWC

[3] Lahiri, S.K., Sinha, R., Tectonic controls on the morphodynamics of the Brahmaputra River system in the upper As-sam valley, India, Geomorphology (2012)

[5]GoswamiD.C., “Managing the Wealth and Woes of the River Brahmaputra” available at

[7]EnvironmentAssessmentReport  SiangBasin In Arunachal Pradesh, Interim Report June 2012, Prepared for Central Water Commission(CWC)

[9] Goswami D.C., “Managing the Wealth and Woes of the River Brahmaputra” available at

[10] An anabranch is a section of a river or stream that diverts from the main channel or stem of the watercourse and rejoins the main stem downstream.

[11] Lahiri, S.K., Sinha, R., Tectonic controls on the morphodynamics of the Brahmaputra River system in the upper As-sam valley, India, Geomorphology (2012)

[13] Water yield means volume of water drained by unit area of the basin.

[14] “The Brahmaputra River”, India  by D.C. Goswami and P. J. Das in The Ecologist Asia Vol. 11 No 1 January- March 2003

[15] ibid

[16] ibid

[17] “Water Sector Options for India in a Changing Climate” by Himanshu Thakkar, SANDRP, New Delhi, March 2012

[18] ‘Stemming the Flood, Killing Biodiversity’ by Dr. Sanchita Boruah and Dr. S.P. Biswas in The Ecologist Asia Vol. 11 No 1 January- March 2003

[19] Goswami D.C., “Managing the Wealth and Woes of the River Brahmaputra” available at

[24]Barak River is located in south Assam and also an international river but smaller than the Brahmaputra.

Climate Change Hits Assam Tea

The flavour has changed from what it was before. The creamy and strong flavor is no more. It has been revealed that the changes have already been observed everywhere in the Indian tea industry and scientifically it is established that these are gravely attributed to excessive use of pesticides attributed to climate change. Other factors like cultivation methods might also be partly responsible. Studies by  scientists  including Toklai Experimental Station (TES) at Jorhat, Assam has also revealed these  changes.

Excessive pesticide residues in tea continue to be a concern among exporters. These pesticides used in tea plants generally fall in two groups: organochlorines organophosphates and pyrethrins. The chemicals used in tea cultivation are dicofol, endosulfan, ethion, fenzaquin and parquet among others. But all tea producing countries do not have the same standard regarding use of pesticides. The pesticide levels in tea measured from some countries are not within acceptable levels.

Assam tea is acclaimed worldwide for its distinctive taste, and if this is affected, it could spell doom for exports in the long run. According to TAI estimates, the average price realization from exports have been quite discouraging in recent years due to major improvement in production by Sri Lanka and Kenya, India’s two major rivals in the export market.

Scientists from TES, the oldest tea research station in the world, said rainfall and minimum temperature were two of the most important factors affecting both quality and quantity of harvests. The decline has been taking place although there has been an increase in the area of tea cultivation as new gardens have come up, and many gardens have added new areas for tea plantation. This is an indication of the seriousness of the threat. A rise in temperature and change in rainfall pattern are threatening the production and quality of India’s Tea.

Rainfall in North-east India has dropped by more than one-fifth in the past 60 years and the minimum temperature has increased by 1.8 degrees to 67.1 Fahrenheit. A rise in temperature and change in rainfall pattern are threatening the production and quality of Indian Tea. The average rainfall in NE India ranges from 2000-4000 mm. However more than total amount the distribution of rainfall matters a lot for sustained high yield of tea throughout the season. In the NE India, the rainfall distribution is not even. The excess rainfall in the monsoon months of June – September causes drainage problems.

The average monthly rainfall during November to March is less than the evaporation loss and the resulting soil moisture deficient affect tea bushes. When this dry spell persists for a longer period, tea plants suffer heavily and crop goes down in spite of having sufficient
rainfall in the monsoon.

A study earlier conducted by the TES had found that the average minimum temperature in Assam had risen by 1 degree Celsius in last 90 years, besides the region losing around 200 mm rainfall because of climatic changes. Temperature affects tea yield by influencing rate of photosynthesis and controlling growth and dormancy. In general, the ambient temperature with 13 degree C and 28-32 degree C is conductive for growth of tea. Maximum ambient temperature above 32 degree C is unfavourable for optimum photosynthesis more so if it is accompanied by low humidity. In the tea belts of the region the average winter minimum temperature (Dec- Feb) remains below 12 degree and there is hardly any growth during this period.

About 850 tea gardens in Assam produce 55 per cent of India’s tea, but crop yield are decreasing and amid fears of a co relation with environmental change. Assam is the largest tea producing state of India and accounts for around 55 per cent of total tea produced in the country. Though Assam witnessed a bumper tea production in 2009, thus bringing the industry out of 10 years of recession, production took a hit last year due to excessive rainfall. From 499 million kg in 2009, the figure dropped to 480 million kg in 2010 in Assam. Total tea production in India in 2010 was 966 million kg.According to Tea Board estimate Assam produced 512,000 tonnes of tea in 2007. By 2008 this had declined to 487,000 tones, with estimated production in 2009 down again to 445,000.

Fortunately the output in Assam, the largest tea-producing state, was up 5 per cent to 607.83 million kg in the April-December period of 2013-14, from 577.13 million kg in the year-ago period. Of course this has happened on account of vast cultivation area extension by small tea-growers. Climate change makes bound and unavoidable the profuse uses of
fertilizers and pesticides in tea cultivation which degrades both quality and quantity of Assam and Darjeeling tea, a section of tea cultivators and experts said. A steady decline or an almost stagnant picture shown in tea production has been blamed on climate change.

What’s really scary is that this change in climate seems to be affecting the tea’s flavour. Researchers from TES said that some 41 species of mirids in the genus Helopeltis have so far been described in the world and most of them in India. In recent years, two species of Helopeltis, H. schutedeni Reuter (Hemipetra: Miridae) and as earlier predicted, H. thievora waterhouse, have become the greatest enemies of tea planters in India or Asia I but in Africa causing 55% and 11% to 100% crop loss, respectively. Some bugs are transforming themselves into super bugs, thereby making the common pesticides worthless in the tea gardens of Assam.

Helopeltis (Tea mosquito bug) and looper caterpillar is gradually attaining resistance against common pesticides used in our tea gardens. Helopeltis has been keeping the tea growers scary for the past several years. Constant use of same kind of same kind of pesticides is leading to the transformation of these insects into super bugs much to the anxiety of the tea planters and the scientists as well.

It is almost impossible for Assam tea to survive without use of these chemicals because of the sub-tropical climatic condition in the state where the use of these chemicals are necessary for pest control. The tea industry in India is turning up towards domestic market rather than follow a stricter tea standard. What is alarming is that tea growers are still using harmful chemicals like HCH, DDT, Dicofol, Fenvalerate, Methamidophos, Alphamethrin and Acephate.

A cup of tea that cheers can also be an important route of human exposure to pesticide residues. It is important to evaluate the percent transfer of pesticide residue from dried (made) tea to tea infusion, as tea is subjected to an infusion process prior to human

Chandan Kumar Duarah

First published  in Eurasia Review

Golf course or elephant corridor? NGT clears path for jumbos


New Delhi: Five years ago, the authorities at Numaligarh Refinery Ltd (NRL) in Assam created a golf course and fenced it with a wall resulting in deaths of 12 elephants since then.

The National Green Tribunal (NGT) on Wednesday ordered demolition of the wall and asked the company to pay Rs.25 lakh as restoration fee for the area where the golf course had been developed.

In May 1991, the Union environment ministry granted environmental clearance for the refinery with directions to ensure safe distance from the Kaziranga National Park and sought prohibition of any development within a radius of 15km all round the refinery site.

However, NRL developed a golf course and erected a wall which fell in the way of the elephant corridor. Subsequently, Rohit Choudhury, an environmental activist approached the green tribunal against illegal activities around the No Development Zone (NDZ).

During the hearing, it was brought to the tribunal’s notice that since 2011, at least 12 elephants had died as a result of the construction of the wall.

“As regards the wall with barbed wire fencing which comes in the way of elephant corridor, the same should be demolished. The area, where the wall has come up and the proposed township is to come up is a part of Deopahar ‘PRF’ (Proposed Reserve Forest). It also falls within the No-Development Zone notification, issued by the MoEF in 1996. Thus, the wall should be demolished within a period of one month,” said the NGT bench headed by its chairperson justice Swatanter Kumar.

NRL had also planned a township which falls in the area of the elephant corridor. On this, the tribunal directed that “the proposed township should not come up in the present location.” Hailing the order, Chandan Kumar Duarah, an environmentalist and science writer said the order will also help conserve the archaeological ruins and resources lying in the area. Numali Garh and Alongpira has been encroached by an oil depot businessman and Numaligarh tea estate, Duarah said.