A tunnel under construction on the Teesta River in Sikkim collapsed after a methane gas explosion, killing 12 workers and trapping 13 others, authorities report.
Rescue teams are on the scene about 1.5 km from the tunnel entrance, armed with breathing apparatus and search‑and‑rescue equipment.
The National Hydroelectric Power Corporation (NHPC) said the blast was caused by a sudden burst of methane gas trapped inside the rocks, releasing dense fumes and toxic gases that destroyed the tunnel's supports.
Sikkim's government attributed the incident to methane combustion during tunnelling, stressing the danger of underground excavation in areas with natural gas pockets.
Of the 27 workers inside the tunnel, two emerged unharmed; 25 were trapped, 12 bodies were recovered and 13 remain missing as of early Wednesday.
Victims include a local Sikkim resident and migrants from West Bengal, Uttarakhand and Assam. The cause of each death will be confirmed by post‑mortem examinations.
The National Disaster Response Force (NDRF) is narrowing its search to a 200‑metre zone where the trapped men are most likely located, while a special investigation team led by Chief Minister Prem Singh Tamang is probing the incident’s root causes.
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