India Races to Build Massive Dam as China Proceeds with Mega Hydropower Project in Tibet
India is accelerating plans to build its largest hydroelectric dam in response to China’s construction of a massive hydropower project in Tibet, which New Delhi fears could drastically reduce water flow into its northeastern regions. According to government analysis and sources familiar with the matter, India's concerns include potential water shortages and strategic vulnerabilities.
The planned Chinese dam, announced in December, is set to be built on the Yarlung Zangbo River—known as the Siang in India and the Brahmaputra further downstream. The river originates from the Angsi Glacier in Tibet and is a critical water source for more than 100 million people across China, India, and Bangladesh.
India’s Concerns Over Reduced Water Flow
India’s internal assessment suggests that the Chinese dam could reduce water flow during the dry season by up to 85%, severely impacting agriculture, drinking water, and hydropower in northeastern states, especially Assam. The analysis warns that China could divert up to 40 billion cubic meters of water annually, particularly during the non-monsoon months when water demand peaks.
The construction of the Chinese dam began in July and is estimated to cost nearly $170 billion, although Beijing has yet to disclose full technical details. However, Indian analysts have based their projections on past studies from institutions like the Central Water Commission.
India’s Strategic Response: Upper Siang Dam
To mitigate the risks, India has revived long-pending plans for the Upper Siang Multipurpose Storage Dam in Arunachal Pradesh. If built, it would become India’s largest dam, capable of storing 14 billion cubic meters of water. This storage capacity could significantly reduce the impact of upstream water cuts by releasing water during the dry season.
According to internal projections, the dam could limit water supply losses in key urban centers like Guwahati to around 11%, compared to 25% if no dam is constructed. It could also act as a buffer in the event of sudden water surges caused by the failure or intentional release from Chinese infrastructure upstream.
Indian officials are considering a proposal to keep 30% of the dam’s capacity empty at all times to absorb unexpected water flows and prevent downstream flooding.
Local Resistance in Arunachal Pradesh
Despite strategic urgency, India’s project faces strong resistance from the local Adi community in Arunachal Pradesh. When survey materials were brought to the site in May under police protection, villagers vandalized equipment, destroyed a bridge, and looted police tents. The Adi community, which relies heavily on farming, fears displacement and loss of livelihood.
“The cardamom, paddy, jackfruit, and pear we grow on this land help educate our children,” said Odoni Palo Pabin, an Adi resident and mother of two. “We will fight the dam to the end.”
As many as 16 villages could be submerged, directly affecting 10,000 people and indirectly impacting over 100,000, according to community leaders and local sources.
Government Strategy and Compensation Plans
The Arunachal Pradesh government, led by a member of Prime Minister Modi's party, supports the project, calling the Chinese dam an “existential threat.” The state has initiated talks on compensation for affected families.
NHPC, the state-run hydropower company leading the project, is planning to spend over $3 million on education, health, and emergency services to incentivize relocation. Recently, three villages reportedly allowed NHPC to begin preliminary work, signaling possible progress.
However, India has a long history of public resistance to large dam projects, which have often led to long delays or scaled-down proposals.
Geopolitical Implications and Regional Tensions
India’s response comes amid worsening relations with both China and Pakistan. While Delhi accuses China of manipulating water resources, Pakistan has accused India of doing the same. India recently suspended its participation in a 1960 water-sharing treaty with Pakistan and is considering diverting river flows from its downstream neighbor.
Although an international tribunal ruled that India must honor the agreement, Delhi disputes the tribunal’s authority.
Safety and Environmental Risks
Experts are raising alarms about the safety of large dams in seismically active regions like Tibet and Arunachal Pradesh. Sayanangshu Modak, a water relations expert at the University of Arizona, warned that both regions are prone to earthquakes, landslides, and glacial lake outburst floods—all of which pose serious risks to dam infrastructure and downstream populations.
“These are zones of high seismic activity and extreme weather events,” said Modak. “Dam safety is a legitimate concern and India should engage diplomatically with China on this issue.”
Outlook
Even if India greenlights the Upper Siang project soon, construction could take up to a decade, meaning China’s mega-dam would likely be operational first—projected for the early-to-mid 2030s. This time gap increases India’s vulnerability during the dam’s construction phase, especially if China alters water flows during peak monsoon seasons.
As climate change, geopolitical tensions, and water scarcity converge, the battle over control of transboundary rivers like the Brahmaputra is fast becoming one of the most critical environmental and strategic challenges in South Asia.