Chinese Premier Li Qiang on Saturday inaugurated construction of what is expected to be the world’s largest hydroelectric dam on the Yarlung Tsangpo River in Tibet — a project that has triggered alarm in downstream India and Bangladesh over its potential environmental and geopolitical repercussions.
Attending the groundbreaking ceremony in Nyingchi, a city in the southeastern part of the Tibet Autonomous Region, Premier Li described the mega dam project as a “landmark in China's green transition.” State-run news agency Xinhua reported that the dam, once completed, will have an estimated annual generating capacity of 300 billion kilowatt-hours — three times that of the Three Gorges Dam, currently the world’s largest.
The Yarlung Tsangpo originates in the Qinghai-Tibet Plateau and flows eastward across Tibet before turning south into India, where it becomes the Brahmaputra River, continuing into Bangladesh. The river is vital to millions in all three countries for irrigation, drinking water and ecological stability.
India and Bangladesh have voiced strong apprehensions over the dam's impact on water availability, agriculture, and ecological balance in the region. Indian politicians have even described the dam as a potential “water bomb” — capable of worsening floods during monsoons or choking off flows in the dry season. Some analysts have raised the spectre of “weaponisation of water” by Beijing, which could theoretically manipulate river flows in times of conflict.
Beijing, however, has pushed back against such accusations. The Chinese foreign ministry insists the dam has passed rigorous scientific scrutiny and will neither harm ecological systems nor infringe on the water rights of downstream nations. Officials claim the project will actually help in climate adaptation and disaster mitigation efforts downstream.
Approved as part of China’s 14th Five-Year Plan in 2020, the project will involve the construction of five cascade hydropower stations at an estimated cost of $167 billion. A newly formed state-owned enterprise, China Yajiang Group, has been tasked with overseeing the construction and operation of the massive facility. Vice-Premier Zhang Guoqing, speaking at the company’s inauguration, underscored the importance of ecological protection and technological innovation in the project’s execution.
India, in response, has accelerated its hydropower initiatives in Arunachal Pradesh — a region that Beijing controversially claims as part of southern Tibet. Indian authorities argue that boosting their own infrastructure on the Brahmaputra is a strategic imperative to safeguard national water interests.
The dispute over Arunachal Pradesh adds a geopolitical layer to the dam debate. While India considers the region an integral part of its territory, China’s longstanding claims have been a point of diplomatic contention.
Amid the geopolitical unease, new research by China’s Ministry of Water Resources and Hohai University offers a different perspective. A study based on downstream data from the Zangmu and Jiacha dams — two major upstream facilities operational since 2014 — suggests that fears of drought may be misplaced.
According to the study, low water flows during the dry season increased by over 50 percent in February, with elevated levels observed throughout the season. Flood intensity during peak monsoon periods was also slightly reduced, with peak flows dropping by about 2 percent in August, traditionally the riskiest month for flooding.
Lead researcher Dr Zhang Jianyun, China’s chief dam safety official, noted that such trends contradict concerns expressed in India and Bangladesh. Writing in the peer-reviewed journal Advances in Water Science, Zhang’s team argued that the joint operation of upstream reservoirs has, so far, had a stabilising effect on water flow.
However, the same study also highlighted emerging environmental changes, largely attributed to global warming. Rising temperatures on the Tibetan Plateau — increasing by 0.05°C annually — are accelerating glacial melt, adding substantial volumes of water between June and October. This, in turn, has shifted the thermal and hydrological rhythm of the river system, impacting aquatic life.
“The Yarlung Tsangpo is now a crucial natural laboratory for understanding how large-scale water infrastructure interacts with climate change in alpine river systems,” the researchers said.
As the mega project progresses, it will continue to test the fragile balance between energy development, environmental stewardship, and regional diplomacy. While China touts the dam as a triumph of sustainable engineering and climate adaptation, neighbouring countries remain wary of its long-term implications.
With water emerging as a critical resource in Asia’s future, the Yarlung Tsangpo — and the decisions made around it — may become one of the defining issues of cross-border cooperation or conflict in the region.