Rescue teams in India have recovered the bodies of the final 13 workers who remained trapped inside a collapsed hydropower tunnel, bringing the total death toll to 25 as authorities officially called off the operation on Thursday.
For four days, multiple agencies worked together in a sustained effort following a gas explosion that tore through the tunnel. After all missing workers were accounted for, teams conducted one last inspection of the tunnel site, according to a statement from the state government of Sikkim.
The explosion happened on Monday at the 500-megawatt Teesta Hydroelectric Project, located roughly 40 kilometers — about 25 miles — south of the state capital Gangtok, in the Himalayan state of Sikkim.
Officials said a buildup of methane gas set off the blast, sending dozens of workers underground. The presence of toxic gas inside the tunnel made rescue efforts significantly more difficult throughout the operation.
In response to the tragedy, the government announced the formation of a high-level committee tasked with investigating what went wrong and recommending safety measures to help prevent similar disasters in the future.
Construction accidents are a recurring problem in India, where rapid infrastructure development frequently runs up against unstable geology, lapses in construction practices, extreme weather conditions, and safety challenges.
The Teesta River basin, where the hydropower project is under construction, sits in a seismically active zone characterized by young, unstable rock formations filled with fractures and underground pockets that can contain ancient trapped gases. Experts note that seismic activity and unpredictable underground conditions make tunnel construction in this region particularly dangerous.
This is not the first such tragedy in the area. A coal mine explosion in the neighboring state of Meghalaya killed 18 workers this past February. In 2023, a tunnel collapse in the northern state of Uttarakhand trapped 41 workers underground for 17 days before they were successfully rescued.
