China has started construction of the world’s biggest hydroelectric dam, a project that’s set to be far larger than the Three Gorges Dam — already the world’s biggest single source of green power — and more expensive than the International Space Station.

China is building the world's largest hydropower dam on the Yarlung Tsangpo river, which starts in the Himalayas. However, India and Bangladesh have both expressed concerns over the dam's potential impact.

The dam will be located in the lower reaches of the Yarlung Zangbo. India and Bangladesh have already raised concerns about its possible impact on the millions of people who live downstream.