China begins construction on world’s largest dam raising downstream fears

Chinese authorities have formally begun constructing what will be the world’s largest hydropower dam in Tibetan territory, a colossal project that has immediately sparked grave concerns from India and Bangladesh, the two nations directly downstream on the trans-border river.

Chinese Premier Li Qiang presided over a ceremony on Saturday, July 19, 2025, marking the start of construction on the Yarlung Tsangpo river, a vital waterway that flows through the Tibetan plateau before entering South Asia. Known as the Motuo Hydropower Station, the project is set to cost an estimated 1.2 trillion yuan (approximately $167 billion). When completed, it will dwarf China’s own Three Gorges Dam and could generate three times more energy, a staggering output for a single facility.

“The dam is going to cause an existential threat to our tribes and our livelihoods,” said Arunachal Pradesh chief minister Pema Khandu. “It is quite serious because China could even use this as a sort of ‘water bomb’. Suppose the dam is built and they suddenly release water, our entire Siang belt would be destroyed. In particular, the Adi tribe and similar groups would see all their property, land, and especially human life, suffer devastating effects.”

The immense project has attracted widespread criticism for its potential impact on millions of people in India and Bangladesh, as well as the surrounding environment and local Tibetan communities. Officials and experts have flagged concerns that the new dam, situated in a massive canyon, would empower China to control or even divert the trans-border Yarlung Tsangpo, which flows south into India’s Arunachal Pradesh and Assam states, and eventually into Bangladesh, where it feeds into the Siang, Brahmaputra, and Jamuna rivers.

A 2020 report from the Lowy Institute, an Australian think tank, highlighted the geopolitical stakes, noting that “control over these rivers [in the Tibetan Plateau] effectively gives China a chokehold on India’s economy.” This sentiment was echoed by Indian officials, who have in the past expressed concerns to China about the dam’s potential impact. To counter the perceived threat, India plans to build a hydropower dam on the Siang River, which would act as a crucial buffer against any sudden water releases from the upstream Chinese project.

The dam’s location, in a massive canyon said to be the world’s deepest and longest on land, is a key part of its design.⁹ The site is along a section where the Yarlung Tsangpo river makes a sharp U-turn, a feature known as “the Great Bend,” around the Namcha Barwa mountain.¹⁰ This dramatic geographic feature, where the river drops hundreds of metres in elevation, provides the immense hydroelectric potential. According to reports from the Xinhua news agency, engineers plan to conduct “straightening” work and “divert water through tunnels” to build five cascading power stations, a complex engineering feat designed to maximize energy production.

While Chinese Premier Li Qiang has stated the project will prioritize ecological protection and local prosperity, activists have a different view. They describe the dams as the latest example of Beijing’s exploitation of Tibetans and their land, noting that past protests have been met with harsh crackdowns. Last year, hundreds of Tibetans who had been protesting against another hydropower dam were rounded up, leading to arrests and beatings, with some people seriously injured. The environmental concerns are equally significant, encompassing the flooding of pristine Tibetan valleys renowned for their biodiversity, as well as the danger of building mega-dams in a region rife with earthquake fault lines.

Beijing has positioned the development as a win-win solution, with President Xi Jinping personally pushing a policy called “xidiandongsong,” or “sending western electricity eastwards.” This initiative aims to use clean energy generated in the rural west to power the country’s electricity-hungry eastern metropolises. However, its implementation has continued to strain relations with downstream nations. Bangladesh, for instance, formally sent a letter to Beijing in February requesting more information on the project. China’s foreign ministry has previously responded to India, saying it has a “legitimate right” to dam the river and has considered downstream impacts.