At least 20 workers are confirmed dead after a gas explosion and tunnel collapse at a hydroelectric project in Sikkim, a small state in northeastern India. Rescue officials say the remaining workers who were trapped are unlikely to be found alive. The facility, called Teesta Stage VI, is a large dam and power plant being built by a government-owned company called the National Hydroelectric Power Corporation, or NHPC.

Rajiv Roka, who leads Sikkim's disaster management authority, said 13 bodies had been pulled from the collapsed tunnel as of July 22, 2026. Rescuers have seen another seven to eight bodies inside but cannot reach them because conditions are too dangerous. In total, 25 workers were trapped. Roka said he does not think anyone could still be alive given the conditions inside the tunnel Al Jazeera.

NHPC said the collapse was caused by a sudden release of methane gas — a flammable gas that can be trapped inside rock underground. When workers dig into that rock, the gas can burst out and fill a tunnel quickly. If it builds up enough, a single spark can cause an explosion. Survivors said they heard a loud blast before the tunnel caved in Courthouse News.

Getting to the remaining bodies has been extremely difficult. Water has flooded parts of the tunnel, and methane gas is still leaking from the rock. Heavy monsoon rains — the seasonal downpours that hit South Asia every summer — have made things worse by raising water levels and making the remote site harder to reach Al Jazeera. Before rescue teams can go back inside, they have to check gas levels and pump out water each time.

The Teesta Stage VI project is part of India's effort to build more hydropower — electricity generated by flowing water — in the Himalayan mountains. NHPC is the government's main company for building such projects. The company says it will carry out a full investigation into what went wrong, but for now the priority is recovering the victims Al Jazeera Time.

The bigger picture is that building tunnels in the Himalayas is inherently risky. The mountains are geologically young and unstable, which means rocks can shift, crack, and release trapped gas or water without much warning. India has rules requiring gas monitoring and ventilation systems in tunnels under construction, but enforcing those rules at remote sites high in the mountains has long been a source of debate among engineers and safety advocates.

The death toll could still go up. With several bodies visible but unreachable and no survivors expected, the final count depends on whether conditions improve enough for rescue teams to get back inside safely. Monsoon season in Sikkim usually lasts through September, and no one is sure how stable the tunnel is after the blast. Once recovery efforts end, NHPC's investigation will look at both what triggered the explosion and whether the safety systems in place were good enough for one of India's biggest hydropower projects.