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.

The project, part of China’s push to expand renewable energy and reduce carbon emissions, could affect millions downstream in India and Bangladesh.

The investment is set to benefit hydropower plant and grid equipment makers, but some analysts warn that market enthusiasm may wane soon.

China has declined to comment on the alleged exit ban, saying only that it handles all cases according to the law.

The U.S. State Department said on Monday that the Chinese government had blocked a U.S. Patent and Trademark Office employee visiting the Asian country in a personal capacity from leaving.