Overview
- A large landslide above the Chyakoong River in Mangan district struck during the night of Sept. 5–6 and partly blocked flow at the confluence with the Teesta.
- The collapse occurred along a newly cut section of the Naga‑Tosa Road opposite the Theng Tunnel, linking the failure to recent roadside excavation.
- Both the Teesta and Chyakoong now carry muddy, pooled water through the affected stretch but continue to flow and show no immediate rise at observation posts.
- Local police at Chungthang and Theng are monitoring the site, the Police Control Room has been told to alert lower‑belt vulnerable areas, and authorities have advised people to stay away from riverbanks.
- The Teesta supplies downstream towns and roads, so officials are watching for further blockage that could trigger flash flooding, damage infrastructure or require evacuations if water release changes suddenly.