China has formally started construction of a massive USD 167.8 billion hydropower dam on the Brahmaputra River (Yarlung Zangbo) in Tibet near Arunachal Pradesh. The project, consisting of five cascade dams at Nyingchi’s Mainling, is expected to generate over 300 billion kWh annually and power over 300 million people. It has raised concerns in India and Bangladesh over water control and potential flood risks during conflicts. Despite earthquake risks in the tectonic zone, China assures safety and ecological care. India is also building a dam on its side. The project dwarfs China's Three Gorges Dam and could reshape regional water dynamics.