LUCKNOW, Feb. 15 -- The National Green Tribunal (NGT) has directed the Uttar Pradesh government to physically demarcate floodplains along the Ganga, its tributaries, and the Yamuna to prevent further encroachment that has constricted waterways, increased pollution, and raised flood risks.

Unauthorised construction, slums, and urban sprawl have severely affected the river's ecosystem by altering natural riverbanks, experts said. The encroachments have narrowed the river channel, making areas more vulnerable to flooding.

The tribunal, led by Chairman Justice Prakash Shrivastava and expert member A Senthil Vel, has ordered the state to install around 7,350 boundary pillars across 13 districts from Unnao to Ballia. The demarcation covers Ka...