Hydro-hegemony in the Himalayas: How China is rewriting Brahmaputra’s future

China has started constructing a mega hydro dam on the Yarlung Tsangpo (Brahmaputra) in Tibet’s Medog County, in close proximity to India’s border state of Arunachal Pradesh. This has raised alarm as it has the potential to disrupt water flow downstream, impacting the hydrographic profile of the Brahmaputra River. Chinese Premier Li Qiang announced the launch of the project on July 22, 2025. In fact, this should not have come as a surprise because the ambitious project was part of China’s 14th Five-Year Plan (2021–25). The Chinese maintained strategic silence as work on the dam reportedly began surreptitiously during the Covid-19 period.

The Yarlung Tsangpo River originates from the Angsi Glacier in Burang County of Tibet and flows over a distance of 1,625 km until it makes a loop called the ‘Great Bend,’ just before entering India as the Siang. It traverses 918 km in India through Arunachal Pradesh and Assam, then flows into Bangladesh as the Jamuna for 337 km before draining into the Bay of Bengal. While the Yarlung Tsangpo constitutes 56 per cent of the Brahmaputra’s length, it contributes only about 15 percent of the total water volume. The Brahmaputra is formed in India, specifically in Sadiya, with the confluence of the Siang, Lohit, and Dibang rivers. A major part of the Brahmaputra’s water volume comes from rainfall and snowmelt in the Indian Himalayas and downstream tributaries.

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China’s Grand Design

Water resources in China are unevenly distributed. The developed northern region, home to around 42 percent of the population, has only 14 percent of fresh water. The agrarian south, relatively less developed, is water-rich with 86 percent of the share. Over the years, industrial and domestic water usage in China has increased significantly, compelling it to resort to water politics to sustain economic growth. The Tibetan plateau is home to rich water resources as 100,000 sq km of its area is covered with glaciers, which feed twelve major rivers in South and Southeast Asia.

China, being the largest consumer of energy, aims to achieve net-zero emissions by 2060. To this end, it has planned to double its hydroelectric generation capacity in the next couple of years. As per the Chinese Academy of Social Sciences, the generation capacity of the Yarlung Tsangpo basin is around 114 GW. Therefore, for over a decade, China has been building a series of dams on the Yarlung Tsangpo and its tributaries. Major ones already completed or nearing completion include Zangmu (510 MW), Dagu (640 MW), Jiecha (360 MW), Jiexu (560 MW), and Bayu (780 MW).

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China has also undertaken the ‘South–North Water Transfer Project’ to divert water from the Yangtze River along two routes. The Eastern route utilizes the Grand Canal, while the Central route involves diverting water from the Han River (a Yangtze tributary) to Beijing. The Western route, still in the planning stage, would involve diverting Yarlung Tsangpo water from the Namcha Barwa area, where construction of the mega dam has just started. This could significantly impact water resources in India and Bangladesh, causing potential shortages during the lean period, besides raising environmental concerns.

The ‘Yarlung Tsangpo River Lower Reaches Hydropower Project,’ named the Medog Dam, is expected to be the world’s largest hydropower project. It entails building five cascade hydropower stations with a planned capacity of 60 GW. It will dwarf the Three Gorges Dam (22.5 GW) on the Yangtze River. The project is envisioned to play a significant role in China’s energy strategy, meeting the annual needs of over 300 million people. The total estimated investment is approximately USD 167.8 billion.

Ramifications

China building the Medog Dam has definite geopolitical and ecological consequences with expansive ramifications. It underscores China’s upstream advantage, giving it the potential to manipulate water flow, thus making India—the lower riparian country—vulnerable to Beijing’s coercive tactics of using water as an instrument in future conflicts. Another grave fear is China diverting Yarlung Tsangpo’s flow northwards, as mentioned above. The proximity of the Medog Dam to the Indian border also has security implications.

Given that the Eastern Himalayas are ecologically sensitive and seismically active, large dams in the region pose potential risks of triggering landslides, earthquakes, and ‘glacial lake outburst floods’ (GLOFs), altering the hydrological rhythm. Changes in sediment flow could erode riverbanks, impacting agriculture and livelihoods in the Brahmaputra Basin, besides affecting the navigability of inland waterways. Even water quality could deteriorate due to the flow of construction debris, as the project requires extensive tunnelling—up to 420 km—through the mountain range. This also implies biodiversity loss in one of the world’s richest riverine ecosystems.

India’s Response

India has expressed concerns about China’s dam building on the Yarlung Tsangpo, which are justified given the lack of transparency in China’s authoritarian system and past precedents. Chief Minister of Arunachal Pradesh Pema Khandu has flagged the issue on multiple occasions and remains sceptical of Chinese designs. Assam Chief Minister Himanta Biswa Sarma, on the other hand, perceives that China’s dam could help in controlling floods in the region and believes its exact impact would only be known when the dam is completed—a stance that risks a fait accompli.

Ironically, Delhi has limited leverage as Beijing is not a signatory to the 1997 UN Watercourses Convention, giving it an unchallenged grip over Tibet’s water resources. Additionally, there is no formal framework for sharing Brahmaputra waters. However, there exists an ‘Expert Level Mechanism’ (ELM) that provides the two sides a platform to discuss and share flood-season hydrological data. This arrangement is of limited value due to its short duration and restricted disclosure of information by China. Incidentally, no ELM meeting has been held since June 2023.

India needs to raise the matter with China and push for a binding water treaty. Additionally, in collaboration with Dhaka and Thimphu, Delhi must highlight the issue at global water diplomacy forums. More importantly, to cope with the impact of China building upstream dams on the Brahmaputra, India requires a science-backed comprehensive strategy that is multi-pronged: integrating storage, flood control, transportation, and ecological dimensions. India also needs to enhance satellite monitoring of river flow and weather prediction systems to track changes with precision. Further, international scientific collaboration must be explored to help predict the impact of glacial melt and upstream interventions on Indian rivers.

India has begun to take steps to strengthen its water security. The government has conceived the ‘Siang Upper Multipurpose Project’ with a 10 GW capacity. The dam will act as a power generator and strategic buffer. While for China, damming the Yarlung Tsangpo is meant to meet its clean energy needs, for India, it is a matter of strategic, ecological, and existential concern. With water becoming the new oil, water politics over rivers is set to intensify. As Beijing is unlikely to heed Delhi’s concerns, it is imperative for India to formulate a long-term policy and plan of action to safeguard its vital national interests in the wake of China’s hydrographic aggression.

The author is a war veteran, former Assistant Chief, served as Defence Attaché in China and North Korea; currently Professor of Strategic-IR & Management Studies. Views expressed in the above piece are personal and solely those of the author. They do not necessarily reflect Firstpost’s views.