At least nine people have been killed and 15 others remain trapped after a tunnel collapsed at an under-construction hydropower project in India’s northeastern state of Sikkim, officials said on Tuesday.
The incident occurred on Monday while workers were constructing a tunnel for a state-run hydroelectric project on the Teesta River, prompting a large-scale rescue operation in the remote Himalayan region.
Rescue Operation Underway
According to Rajiv Roka, Director of the Sikkim State Disaster Management Authority, authorities estimate that between 25 and 27 workers were trapped when the tunnel collapsed.
“So far, nine bodies have been recovered,” Roka told AFP, adding that rescue teams are continuing efforts to reach those still believed to be inside.
Specialised rescue personnel remain at the site as authorities work to clear debris and search for survivors.
Toxic Gas Complicates Rescue Efforts
Officials said rescue operations have been made significantly more difficult due to the presence of toxic methane gas leaking from underground rock formations.
Only teams equipped with oxygen-breathing apparatus have been allowed to enter the tunnel because of the hazardous conditions.
“Aggressive rescue operations are underway, but the problem is there’s a lot of gas present there,” Roka said.
To strengthen the rescue mission, a specialised team trained in handling mining and underground tunnel accidents has been flown to Sikkim to assist local authorities.
Cause Yet to Be Confirmed
Authorities believe the collapse may have been triggered by an underground blast, although the exact cause has not yet been determined.
Roka said officials were unable to immediately establish the source of the blast because it occurred deep inside the tunnel, adding that it was “most probably natural.”
The Himalayan region has also experienced heavy monsoon rainfall in recent days, although investigators have not confirmed whether the weather contributed to the incident.
Infrastructure Safety Concerns
Large-scale construction accidents are relatively common in India, particularly at major infrastructure projects.
Environmental experts have repeatedly warned that rapid development in the ecologically fragile Himalayan region has increased the risk of landslides, tunnel failures and other construction-related disasters.
In 2023, a similar incident in the northern state of Uttarakhand saw 41 workers trapped inside a collapsed road tunnel for 17 days before they were successfully rescued, highlighting the challenges of conducting rescue operations in mountainous terrain.
