Among them are fears that the construction of the dam – first announced in late-2020 – could displace local communities, as well as significantly alter the natural landscape and damage local ecosystems, which are among the richest and most diverse on the Tibetan Plateau.

China has built several dams in Tibetan areas – a contentious subject in a region tightly controlled by Beijing ever since it was annexed in the 1950s.

Activists have previously told the BBC that the dams are the latest example of Beijing’s exploitation of Tibetans and their land. Mainly-Buddhist Tibet has seen waves of crackdowns over the years, in which thousands are believed to have been killed.

Earlier this year, the Chinese government rounded up hundreds of Tibetans who had been protesting against another hydropower dam. It ended in arrests and beatings, with some people seriously injured, the BBC learned through sources and verified footage.

They had been opposing plans to build the Gangtuo dam and hydropower plant, which would displace several villages and submerge ancient monasteries with sacred relics. Bejing, however, said it had relocated and compensated locals, and moved the anicent murals to safety.

In the case of the Yarlung Tsangpo dam, Chinese authorities have stressed that the project would not have major environmental impact – but they have not indicated how many people it would displace. The Three Gorges hydropower dam required the resettlement of 1.4 million people.

Reports indicate that the colossal development would require at least four 20km-long tunnels to be drilled through the Namcha Barwa mountain, diverting the flow of the Yarlung Tsangpo, Tibet’s longest river.

Experts and officials have also flagged concerns that the dam would empower China to control or divert the flow of the trans-border river, which flows south into India’s Arunachal Pradesh and Assam states and onwards into Bangladesh.

A 2020 report published by the Lowy Institute, an Australian-based think tank, noted that “control over these rivers [in the Tibetan Plateau] effectively gives China a chokehold on India’s economy”.

Shortly after China announced its plans for the Yarlung Tsangpo dam project in 2020, a senior Indian government official told Reuters that India’s government was exploring the development of a large hydropower dam and reservoir “to mitigate the adverse impact of the Chinese dam projects”.

China’s foreign ministry has previously responded to India’s concerns around the proposed dam, saying in 2020 that China has a “legitimate right” to dam the river and has considered downstream impacts.