India tunnel collapse at a hydropower project kills 10 as 17 remain missing

What the report says

Al Jazeera, citing officials and reporting from Reuters and The Associated Press, reported that at least 10 people were killed and 17 remained missing after a suspected gas explosion caused a tunnel collapse at a hydropower project in India’s northeastern Sikkim state. The incident occurred Monday in Samardung village, in the Himalayan region near the borders with Bhutan and Tibet, and was reported on July 21, 2026.

The tunnel was under construction as part of a 500-megawatt project on the Teesta River for the state-owned National Hydroelectric Power Corporation, or NHPC. Officials said workers were inside when a loud blast was heard and debris fell through the tunnel. NHPC said a sudden release of gas, believed to be methane trapped in or around rock formations, was suspected of causing the explosion. Officials also said six NHPC personnel who entered to help with the response became trapped.

Rescue operations were being carried out by teams including India’s National Disaster Response Force, but Al Jazeera reported that dangerous conditions inside the tunnel were hampering access. An NDRF official said methane, carbon monoxide and hydrogen sulphide had been detected, requiring rescuers to use specialised breathing equipment while searching for possible survivors.

The report noted broader safety concerns around major construction in the Himalayas, where seismic activity and unstable geology can make tunnelling hazardous. As context, it cited the 2023 Uttarakhand tunnel collapse, in which 41 workers were trapped for 17 days before being rescued, and expert warnings that the Teesta basin’s fractured rock can contain underground gas pockets.