The Ghost Gas in the Mountain: Why Himalayan Tunnels Become Subterranean Explosives: Santa tries to light a match inside a hot, humid hydro tunnel, dismissing a foul sulfuric odor. Banta intercepts the ignition using multi-gas telemetry, evoking the deadly methane flash in Sikkim and boiling aquifer inrushes in Tapovan and Simplon to explain why subterranean chemical and thermal traps demand automated early warning.