India tunnel collapse death toll rises to at least 20

The death toll from a tunnel collapse at an under-construction hydroelectric project in India's remote northeast has risen to at least 20, officials said Wednesday.

The collapse happened on Monday in Namchi district in the Himalayan state of Sikkim, where workers were building a tunnel for a state-run hydropower project on the Teesta river.

Rajiv Roka, director of the Sikkim State Disaster Management Authority, said 25 people had been trapped. He said 13 bodies had been recovered and rescuers had seen seven to eight more bodies inside the tunnel but had not yet been able to retrieve them.

Officials said water-logging and methane gas leaking from underground rock formations were slowing rescue work. Roka said water at the site was about two-and-a-half feet, or 0.76 metres, deep, making it difficult to retrieve bodies. He said that, given the conditions, he did not think there could be any survivors.

The region has had torrential monsoon rain in recent days.

The National Hydroelectric Power Corporation said the collapse was triggered by an explosive release of suspected methane gas trapped or embedded in rocks, producing dense smoke and toxic gases. The company said a detailed investigation would be carried out to determine the cause.

Accidents at large infrastructure construction sites are common in India. Environmental experts say heavy development in fragile Himalayan areas has contributed to more disasters. In 2023, 41 workers were rescued after 17 days trapped under a collapsed Himalayan road tunnel in Uttarakhand state.