Eight workers were killed after a landslide led to an under-construction tunnel collapsing in Namchi district of Sikkim on Monday, PTI quoted Chief Minister Prem Singh Tamang as saying.The National Hydroelectric Power Corporation tunnel was being constructed in the Samardung area for the Teesta Stage VI Hydroelectric Project.Around 27 workers were trapped inside after the landslide blocked the entrance of the tunnel, PTI quoted unidentified officials as saying. A gas leak was also suspected at the site as several rescue workers experienced dizziness and lost consciousness while trying to reach the trapped persons, according to the news agency. The gas is believed to be leaking from underground strata or rock formations disturbed by the landslide, officials were quoted as saying. With several workers still being trapped in the tunnel, rescue work is ongoing, ANI quoted Namchi Information and Public Relations Department as saying.VIDEO | Several workers are feared trapped inside an under-construction tunnel in Sikkim's Namchi district after a landslide blocked its entrance and triggered a suspected gas leak on Monday afternoon. Visuals from the incident site as rescue operations continue.#Sikkim… pic.twitter.com/JfzXgGMWHO— Press Trust of India (@PTI_News) July 21, 2026