A collapse at the NHPC Teesta Stage VI Hydroelectric Project tunnel in Samardung, Namchi, Sikkim, likely triggered by a landslide and methane gas, disrupted rescue operations due to toxic fumes, waterlogging and low oxygen. The incident left 10–11 workers dead and 15–17 reportedly trapped, with 25 people initially inside when the tunnel collapsed. Rescue teams including NDRF, SDRF, Sikkim Police, district administration, Fire and Emergency Services, mining rescue units and NHPC are working to reach those inside. Resources are being deployed round-the-clock to stabilise the site, though gas and debris continue to hamper efforts and some rescuers have fallen ill. Officials, including Union Minister Gadkari, Sikkim Chief Minister Prem Singh Tamang and Prime Minister Narendra Modi, expressed condolences and aid readiness. Geologist Anish Mohan of Kerala is among those feared trapped, underscoring the human cost of the disaster.