About ten construction workers have lost their lives, and more than 18 others are feared trapped underground following a landslide inside an under-construction hydroelectric tunnel in north-eastern India. The incident, which occurred in the state of Sikkim, triggered a suspected methane gas leak that has severely hindered ongoing rescue attempts.
Emergency services have successfully brought 12 survivors to the surface so far. Specialist teams from the National Disaster Response Force alongside local emergency agencies are continuing search efforts inside the mountain passageway.
The disaster struck at around 3:09 pm on Monday inside the Samardung tunnel in South Sikkim. Infrastructure firm Patel Engineering was actively constructing a section of the Teesta Stage VI Hydroelectric Project when the collapse occurred.
Official statements from the Chief Minister's Office confirmed that emergency operations remain active, though authorities are still working to establish the precise number of personnel trapped inside the structure.
Early findings suggest that an internal rockslide blocked the main passage, sealing off the exit for those working deeper in the shaft. The subsequent release of toxic methane gas rendered the air inside unsafe, preventing search crews from reaching the affected section safely.
Response teams include the State Disaster Response Force, Sikkim Police, and local fire services. Local authorities have closed nearby roads to give emergency vehicles clear access to the construction complex.
Namchi District Collector Anupa Tamling reported that emergency units from Siliguri and Pakyong were deployed immediately after the alarm was raised.
Firefighters and police officers initially attempted to enter the shaft twice without specialised breathing apparatus. However, toxic air conditions forced both teams to retreat before they could locate survivors.
A specialised disaster unit later evacuated the affected first responders, allowing a secondary team equipped for hazardous environments to re-enter the shaft and continue the search.
High concentrations of methane gas inside the tunnel prevented rescuers from getting close to where the missing workers are believed to be located.
District Collector Anupa Tamling added that investigators are still looking into the exact trigger for the internal collapse. Surviving workers who managed to escape reported hearing a sudden, loud explosion before fleeing toward the tunnel exit.
Official figures regarding those trapped remain provisional as teams work to clear debris and monitor air quality levels inside the complex.
Several members of the initial emergency response unit suffered from severe dizziness and breathing difficulties after inhaling methane gas. All affected personnel were brought back to the surface and transported to a nearby medical facility for treatment.
