China’s decision to build the world’s largest hydropower dam in Tibet has raised serious concerns in India, where officials fear the project could cut water flows of the Brahmaputra River by as much as 85% during the dry season. The Yarlung Zangbo, which originates in Tibet, flows into India as the Siang before merging into the Brahmaputra and supports more than 100 million people across China, India, and Bangladesh.
Beijing confirmed construction of the $170 billion dam began late last year in a border county. India’s internal assessments warn that China could divert up to 40 billion cubic meters of water every year, potentially leaving vast parts of northeast India vulnerable during non-monsoon months. Officials fear Beijing could use water control as a strategic tool, with devastating impacts on Indian agriculture and livelihoods.
To counter this, India is moving ahead with its own project – the Upper Siang Multipurpose Storage Dam. Planned as India’s biggest hydropower project, it is designed to store up to 14 billion cubic meters of water. Authorities believe it will reduce Guwahati’s water shortfall and act as a protective buffer against sudden Chinese discharges. By keeping part of the reservoir empty, India hopes to absorb unexpected floods while easing shortages in dry seasons.
However, the project has triggered protests in Arunachal Pradesh, where many locals fear losing land, homes, and farms. Communities dependent on paddy, cardamom, and citrus cultivation worry that the dam will destroy their livelihoods. At least 16 villages risk submergence, displacing around 10,000 people. Tensions have already led to violent demonstrations, though some villages have begun cooperating after promises of compensation and development.
China insists its dam will not harm downstream nations, saying safety and environmental studies were carried out. But Indian officials remain unconvinced. Experts also warn that both mega-dams are being built in seismically active zones, where earthquakes, landslides, and glacial bursts could create catastrophic risks.
The dispute over river control comes at a time of wider regional tensions. India itself has been accused of using water as leverage after suspending cooperation under the Indus Waters Treaty with Pakistan. Analysts say the battle over rivers could worsen already-strained India-China ties, especially with both projects expected to take years before completion.
For now, the people of Arunachal Pradesh remain caught in the middle of this geopolitical contest, uncertain whether the dams will bring security and development or deepen destruction and displacement.
