At least 10 people were killed and 17 others remain missing after a suspected gas explosion caused a tunnel collapse at an under-construction hydropower project in India’s northeastern state of Sikkim, near the Chinese border. The blast occurred Monday at the 500-megawatt Teesta hydroelectric project in Samardung village, approximately 25 miles from the state capital, Gangtok.
Survivors reported hearing a loud explosion before debris fell, trapping workers inside the tunnel. Six officials from the state-owned National Hydroelectric Power Corporation (NHPC), involved in building the project, became trapped while attempting to assist in rescue operations.
Rescue teams, including the National Disaster Response Force (NDRF), are facing hazardous conditions inside the tunnel, where toxic gases such as methane, carbon monoxide, and hydrogen sulfide have accumulated. Rescuers are using specialized breathing equipment to search for survivors amid the dangerous air quality.
Construction accidents are a recurring issue in India, often attributed to rapid infrastructure development in geologically unstable areas, coupled with construction lapses, extreme weather, and varying safety standards. The Himalayan region, in particular, presents significant risks for tunnel projects due to its fragile mountains, seismic activity, and unpredictable underground conditions.
In 2023, a tunnel section in northern Uttarakhand state collapsed, trapping 41 workers for 17 days before their rescue. Experts note that the Teesta River basin, where the current project is located, is a seismically active region with young, fractured rock formations that can contain ancient gas pockets. Geologists suggest that accumulated underground gases could have triggered the explosion. Some formations in the area are associated with coal-bearing strata, which can harbor methane.