On Monday afternoon, a landslide sealed off the entrance of an under-construction tunnel in Namchi district, Sikkim, trapping close to 27 workers inside. The collapse also raised fears of gas building up inside the enclosed tunnel, turning what was already a difficult rescue into an even more dangerous one.
Exact headcount still being confirmed
Officials said the precise number of workers trapped has not been fully established yet. Early information shared by the district administration pointed to 21 workers employed by contractor Patel Engineering and 6 employees of NHPC being stuck inside the tunnel, together adding up to the reported figure of around 27. Authorities said the actual count on the ground was still being verified even as rescue work continued.
Alert came in around 3:40 pm
Namchi District Magistrate Anupa Tamling said the administration was alerted to workers being trapped inside the tunnel at around 3:40 pm on Monday afternoon. Relief and rescue teams were rushed to the site immediately after that alert came in. The operation currently involves the National Disaster Response Force (NDRF), the State Disaster Response Force (SDRF), district police and Fire and Emergency Services personnel, all working together at the site. A specialised rescue team was also called in from the neighbouring state of West Bengal, arriving with equipment specifically meant to handle gas exposure during the operation.
Gas leak turns dangerous, rescuers faint
The gas present inside the tunnel has emerged as the single biggest hurdle for rescuers trying to reach the trapped men. Officials said several members of the rescue teams felt dizzy and even fainted after coming into contact with the gas while working inside the confined space. The suspicion among officials is that the landslide altered the rock layers and strata underground, causing gas to escape naturally from inside the earth as the ground shifted.
Separately, a post on X on July 20, 2026, said that all 16 workers trapped inside the tunnel, referred to there as the Samardung tunnel at Mamring in South Sikkim, had been rescued after the landslide was said to have triggered a suspected gas leak inside it, with teams from the Sikkim Police and Fire and Emergency Services named as part of the rescue effort described in that post.
Methane, cramped space and poor visibility
The district magistrate said the presence of methane gas inside the tunnel, combined with the confined space and poor visibility, has made the rescue operation extremely risky for everyone involved. Rescue personnel are using gas masks, oxygen equipment and other protective gear before entering the tunnel to search for the trapped workers. Ambulances have also been kept ready at the site so that medical help can be provided immediately in case of any emergency during the operation. Officials said the immediate priority remains getting every trapped worker out safely, and that a detailed inquiry into what caused the accident will only follow once the rescue operation is complete.
Tunnel was part of NHPC's Teesta Stage-VI project
The tunnel under construction was part of NHPC's Teesta Stage-VI hydroelectric power project, with the construction work being carried out by Patel Engineering Company. Sikkim's hilly terrain has a history of being vulnerable to landslides and other natural disasters, and continuous rainfall combined with slope failures in these hill regions frequently creates fresh challenges for authorities working in the area. For now, the administration and rescue agencies are working on a war footing to reach every worker trapped inside the tunnel and bring all of them out safely before assessing what went wrong.
