Rescuers say flooding and toxic gas in the collapsed tunnel make it unlikely any remaining trapped workers survived.

The death toll from a gas explosion that caused a tunnel to collapse at a hydroelectric project under construction in the remote northeastern Indian state of Sikkim has risen to at least 20 people.

“Out of the 25 who were trapped, 13 bodies have been recovered so far,” said Rajiv Roka, director of the Sikkim State Disaster Management Authority. “The rescuers have also seen seven to eight more bodies inside, but they have not been able to retrieve them so far.”

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Rescue efforts at the 500-megawatt project for the state-owned National Hydroelectric Power Corporation (NHPC) were hampered because the tunnel was waterlogged and methane gas was leaking from the underground rock formations.

“There was a collection of water … so it’s been difficult to retrieve the bodies,” Roka said. “Looking at the condition, I don’t think there could be any survivors.”

The region has seen torrential monsoon rains in recent days, complicating recovery work.

The NHPC, which is overseeing the hydroelectric project, said in a statement the tunnel’s collapse was triggered by an “explosive release of suspected methane gas trapped/embedded in the rocks, resulting in the generation of dense smoke and toxic gases”.

It said a detailed investigation would be conducted.

Accidents at large infrastructure sites are common in India, but environmental experts say a surge in development projects has triggered more disasters in the ecologically fragile Himalayan region, where seismic activity and unstable rock formations make tunnelling especially risky.

In 2023, 41 workers were rescued after being trapped for 17 days when a Himalayan road tunnel collapsed in the northern state of Uttarakhand.

Source: https://www.aljazeera.com/news/2026/7/22/death-toll-from-blast-at-indian-hydroelectric-project-rises-to-20-people?traffic_source=rss