At least 10 people have died and 17 others remain missing after a suspected gas explosion triggered the collapse of a tunnel under construction at a hydropower project in India’s northeastern state of Sikkim, officials said.

The blast ripped through the tunnel on Monday at Samardung village, near the border with Bhutan and Tibet in the Himalayas. Workers were constructing a 500-megawatt project for the state-owned National Hydroelectric Power Corporation (NHPC) on the Teesta River.

Survivors reported hearing a loud explosion before debris crashed through the tunnel, trapping dozens inside. NHPC said in a statement that a sudden burst of gas, suspected to be methane trapped in rocks, caused the blast.

Six NHPC officials who entered the tunnel to assist in rescue efforts also became trapped. Local police chief Sonam Dolma confirmed 10 bodies recovered and 17 feared trapped.

Rescue teams, including the National Disaster Response Force (NDRF), are struggling due to hazardous conditions inside the tunnel, where toxic gases such as methane, carbon monoxide, and hydrogen sulfide have accumulated. NDRF official Nitin Kumar said rescuers are using specialized breathing equipment.

Construction accidents are common in India’s Himalayan region, where seismic activity and unpredictable underground conditions pose risks. In 2023, 41 workers were trapped for 17 days in a tunnel collapse in Uttarakhand. Experts note that the Teesta River basin lies in a seismically active zone with fragile rock formations prone to gas accumulation.

Source: www.aljazeera.com