India has expressed concerns to China regarding the construction of a mega-dam on the Brahmaputra River, seeking transparency and urging discussions with downstream countries. The project, situated on the Yarlung Tsangpo River in Tibet (the Brahmaputra's upper stream), has raised worries about potential impacts on water flow, regional ecosystems, and the livelihoods of those dependent on the river.
The dam, a $167.8 billion hydropower project, is poised to be the world's largest, dwarfing even the Three Gorges Dam on the Yangtze River. Its location at the "Great Bend" of the Yarlung Zangbo, close to the Indian border in Arunachal Pradesh, amplifies India's apprehensions. The formal commencement of construction, attended by Chinese Premier Li Qiang in July 2025, has further heightened these concerns.
India's primary concern revolves around the potential for China to control the water flow into South Asia, particularly affecting the Brahmaputra's course through India and Bangladesh. The Chief Minister of Arunachal Pradesh, Pema Khandu, has described the dam as a potential "water bomb" and an "existential threat," fearing sudden water releases that could devastate the Siang belt. Experts have also cautioned about the risks of flooding due to intentional or unintentional reservoir operations, dam failures, landslides, or earthquakes, especially considering the dam's location in a seismically active zone.
The Indian government has stated in Parliament that it is closely monitoring the situation to safeguard the rights and livelihoods of its citizens in downstream areas. Minister of State for External Affairs, Kirti Vardhan Singh, noted that the project was first made public in 1986 and that India is taking necessary measures, including preventive and corrective actions, to protect its interests. India has urged China to ensure that the interests of downstream states are not harmed by activities in upstream areas.
While China has defended the dam's construction, asserting that it will not negatively impact downstream regions and will aid in disaster prevention, these assurances have not fully allayed India's concerns. China claims the dam will primarily provide renewable energy and boost local economic growth. However, the lack of a formal water-sharing treaty and limited data transparency between the two countries exacerbate the situation.
Some experts suggest India could mitigate potential risks by planning storage on the Brahmaputra system's rivers to absorb flow variations. The Upper Siang project in Arunachal Pradesh, with its high dam, is seen as strategically important for its hydropower potential and as a buffer against Chinese projects in Tibet. Others have pointed out that regulated water flow could potentially help mitigate annual floods in Assam.
Despite existing mechanisms for dialogue, such as the Expert Level Mechanism established in 2006, India continues to push for greater transboundary cooperation, real-time hydrological data sharing, and comprehensive environmental impact assessments to ensure the river's ecological balance and sustainable flow. Some reports indicate that India has already lodged protests through diplomatic channels and is planning its own dam in Arunachal Pradesh as a countermeasure.
