Guwahati, Feb 3: China’s proposed 60,000–70,000 MW hydropower project at Motuo (Medog) on the upper reaches of the Yarlung Tsangpo has triggered serious environmental and strategic concerns in India, particularly in Arunachal Pradesh and Assam.
The project, included in China’s 14th Five-Year Plan, is planned in the Medog region—where the Yarlung Tsangpo takes a dramatic U-turn around the Namcha Barwa peak before entering India as the Siang and later becoming the Brahmaputra. With an estimated capacity nearly three times that of the Three Gorges Dam, it is being described as one of the most ambitious hydropower projects ever attempted.
Experts warn that the location itself makes the project extremely sensitive. The Great Bend of the Yarlung Tsangpo is one of the most seismically active and ecologically fragile zones in the world.
Large-scale construction involving tunnels, underground caverns, diversion channels and flow regulation structures could permanently alter the river’s natural regime.
Eminent geologist and retired Dibrugarh University professor Jogendranath Sharma has termed the proposed Medog Hydropower Project an ecological and geopolitical threat.
“The low-lying areas of Assam will be directly vulnerable if there is any upstream manipulation of flow. China will gain control over the river system. This is not just an environmental issue, it is also a national security concern,” Sharma said.
Unlike many river basins in northern India, Assam has no major upstream storage infrastructure on its side of the border to cushion sudden water releases or flow disruptions. Any abrupt release of water during monsoon or reduction during lean seasons could have serious consequences downstream.
The Brahmaputra—known locally as the Luit—is both lifeline and destroyer in Assam. It sustains agriculture, fisheries and livelihoods, but its annual floods also displace thousands. The river’s sediment-rich flow maintains fertile floodplains; any alteration in sediment transport could destabilise ecosystems and river morphology.
Environmentalists argue that large dams inevitably alter sediment flow, water temperature and seasonal discharge patterns. They point to the Mekong River experience as a cautionary example. A 2020 study by Eyes on Earth, using river gauge data and satellite-based remote sensing, linked unusually low Mekong water levels to upstream water retention by Chinese dams. Reports have also documented sharp daily water fluctuations and an estimated 80% reduction in sediment load due to dam construction along the river.
“The idea of taming such a powerful transboundary river carries enormous ecological risk. Rivers that have flowed freely for centuries cannot be mechanically regulated without consequences,” an environmentalist said.
There are also concerns about potential water diversion. Some estimates suggest that China could divert significant volumes of water annually, affecting downstream flow during the non-monsoon months. For Assam’s cities, including Guwahati, this could mean reduced water availability during lean periods.
Beijing has maintained that the project will follow international standards and will not harm downstream countries. India, however, has consistently raised the issue through diplomatic channels and is closely monitoring developments.
Beyond hydropower, the project has deep geopolitical implications. The Brahmaputra is a transboundary river flowing from China to India and Bangladesh. Any large-scale infrastructure on its upper reaches introduces strategic leverage over downstream nations.
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