3 September 2025, NIICE Commentary 11667
Esha Sharma
When India recently announced the suspension of the Indus Water Treaty with Pakistan, it was more than just a diplomatic rebuke. It signalled that water, once treated as a shared natural resource, is now considered a strategic asset and, more significantly, a potential weapon. China has confirmed construction of the world’s largest hydropower dam on the Yarlung Zangbo, known is India as the Brahmaputra, just before it enters Arunachal Pradesh. This project is unprecedented in scale, with sweeping ecological, environmental and geopolitical implications for South Asia.
China’s Megadam: Strategic and Environmental Risks
Around two months ago, Chinese Premier Li Qiang announced a major hydropower project in the lower reaches of the Yarlung Zangbo River. The USD137 billion project is believed to generate 300 billion kilowatt-hours of electricity annually and is three times bigger than the Three Gorges Dam, the world’s biggest hydropower station.
The same river is known as the Brahmaputra in India and flows through Arunachal Pradesh and Assam before entering Bangladesh to finally drain into the Bay of Bengal. It sustains irrigation, fisheries, inland transportation and enriches agriculture through fertile silt deposition. There are estimates that China can divert as much as 40 billion cubic metres of water, according to Reuters. This could lead to a reduction of 11 percent of the water supply to the major city of Guwahati, which is highly dependent on water-intensive industry and farming. The effects of this would multiply in dry seasons, impacting the overall ecological balance of India’s northeast region.
China has conveyed that the project is being undertaken keeping in view safety and environmental protection but many in India are concerned about the strategic risks. The Chief Minister of Arunachal Pradesh, Pema Khandu, termed the project a ‘water bomb’ and said it can become an ‘existential threat’ to the region’s tribes and livelihood. The two neighbours are already wary of each other since the Galwan clashes and this could become another bone of contention.
Beyond politics lies the question of environmental concerns. The eastern Himalayas, where the dam is to be built, are among the world’s most seismically active zones and experience extreme weather conditions. Experts have warned that any structural failure, triggered either by natural disaster or technical error, could unleash devastation downstream and potentially flood Arunachal Pradesh and Assam with catastrophic force. Scientists described this as reservoir-triggered seismicity. The Brahmaputra is the world’s highest altitude major river and the dam could trap sediments and alter the natural course of the river. The reduction in sediment flow will restrict soil replenishment, alter riverine biodiversity and intensify soil erosion, all of which will not only threaten the agrarian economy of the northeast region but could impact the entire fragile Himalayan ecosystem.
By positioning the dam just before it enters India, China can leverage it as a geopolitical instrument. The mega dam allows China to manipulate downstream flows. It could hold back water in the lean seasons, unleash sudden water flow downstream or gradually degrade ecosystems by entrapping sediment. Even without openly weaponising water, Beijing‘s unilateral control might cast a long shadow over India’s northeast. China already claims India’s Arunachal Pradesh as ‘South Tibet’ and the border clashes of 2020 in Ladakh have kept the tensions raised. For India, this project is not solely about water availability but also about the broader spectre of ‘Hydro Hegemony’, where rivers become instruments of power politics. Moreover, it could tilt the balance of power in a region where China already maintains a heavy infrastructure dominance.
The Way Forward for India
India must clear the roadblocks in the way to the Upper Siang Project to ensure the security of its downstream communities in Assam and Arunachal Pradesh. The Upper Siang Hydroelectric Project in Arunachal Pradesh has a proposed capacity of 11,000 MW and a storage capacity of 9 billion cubic metres (BCM). This project would mitigate the risk posed by the Chinese actions. Jointly developed by National Hydroelectric Power Corporation (NHPC) and North East Electric Power Corporation Limited (NEEPCO) at an estimated cost of INR 1.13 lakh crore (USD13 billion), the project is designed to stabilise river flows, absorb excess floodwaters and ensure water security. It will produce approximately 47,000 MU in a year, out of which 12 percent will be given free to Arunachal Pradesh. Along with the free power of 1320 MW per year, the Upper Siang Hydroelectric Project will become the backbone of the state's economy. Apart from generating revenue from free power, it will also improve livelihoods through fisheries, transportation, tourism, and employment. Moreover, the project will contribute to climate resilience by preventing the release of 32 million tonnes of CO2 annually compared to coal-based power. Therefore, the imperative for India is to address the local population’s concerns and expedite the construction without any further delay.
A report by CGTN TV in 2023 highlighted that China has already diverted 60 billion cubic metres of water since 2013 through the construction of the South-North Diversion Project to cater to the drought-prone regions of Northern China. The challenge for India will widen if China completes its mega dams before India makes progress on its own strategic projects.
The priority for India, therefore, must be to treat water security as an extension of national security and intensify diplomatic efforts to ensure its concerns are accommodated in China. The Tianjin summit, just a few days ago, has been a constructive development alongside the resumption of flights and issuance of visas. India must leverage this rapprochement with China to voice its concerns regarding the Yarlung Zangbo project while accelerating its own hydropower project development in Arunachal Pradesh. Additionally, India must be prepared for any eventuality that may arise out of the project. This means strengthening disaster preparedness in the northeast, investing in resilient infrastructure and devising strategies to address downstream vulnerabilities.
Conclusion
The lesson of the Three Gorges Dam is clear: the world ignored the warnings, and today its damage is irreversible. To repeat that mistake on the Brahmaputra would be disastrous. Water, the very source of life, is being turned into a weapon of power. India cannot afford to be a passive spectator. It must act now: diplomatically, strategically and domestically, before this upstream project reshapes not just rivers, but the very balance of Asia’s future.
Esha Sharma is an independent researcher with a Master’s in Defence and Strategic Studies from Rashtriya Raksha University.
The views expressed here are the author's personal views.
