India, Jan. 11 -- China's vast South-to-North Water Diversion Project (SNWDP), the largest hydraulic engineering venture ever attempted, along with its relentless dam construction across the Tibetan Plateau, is reshaping Asia's rivers with consequences that stretch far beyond its borders. What Beijing frames as domestic infrastructure has, in effect, become a form of hydrological coercion-one that threatens water security for tens of millions downstream, from Bangladesh to Vietnam. By mid-century, these interventions could displace up to 50 million people, cripple fisheries, and undermine the livelihoods of nearly 200 million farmers.

The SNWDP alone diverts around 45 billion cubic metres of water each year from China's water-rich south ...