An explosion in the tunnel, suspected to have been caused by methane trapped in or released from rocks, filled it with dense fumes and toxic gases, trapping 25 people.

Incident occurred on Monday in Sikkim, where workers were constructing a tunnel for a state-run hydropower project; official says around 25-27 people trapped.

At least nine people have died and 15 others remained trapped after a tunnel collapsed at an under-construction hydroelectric project in India's remote northeast, officials said…

Ten people died and twenty-five personnel were trapped after a methane gas burst. The explosion occurred inside an under-construction tunnel at the Teesta Stage VI Hydroelectric…