{"id":115239,"date":"2026-07-26T10:20:35","date_gmt":"2026-07-26T04:50:35","guid":{"rendered":"https:\/\/vajiramandravi.com\/current-affairs\/?p=115239"},"modified":"2026-07-26T12:33:51","modified_gmt":"2026-07-26T07:03:51","slug":"sikkim-tunnel-disaster","status":"publish","type":"post","link":"https:\/\/vajiramandravi.com\/current-affairs\/sikkim-tunnel-disaster\/","title":{"rendered":"Sikkim Tunnel Disaster: Methane Blast Highlights Himalayan Infrastructure Risk"},"content":{"rendered":"<h2><b>Sikkim Tunnel Disaster Latest News<\/b><\/h2>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Recently, a <\/span><b>methane gas explosion<\/b><span style=\"font-weight: 400;\"> inside the under-construction Head Race Tunnel (HRT) of NHPC&#8217;s 500 MW <\/span><b>Teesta Stage VI<\/b><span style=\"font-weight: 400;\"> Hydropower Project in Samardung, Namchi district, Sikkim, killed 25 workers.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">The disaster has renewed scrutiny of hydropower infrastructure safety, project management, and the ecological fragility of the Himalayan region.<\/span><\/li>\n<\/ul>\n<h2><b>What Happened<\/b><\/h2>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">A sudden release of methane trapped in rocks near Tunnel 4B triggered an explosion, giving workers little time to escape.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Nineteen employees of Patel Engineering Ltd and six personnel of PRW Manpower were inside the tunnel at the time; all 25 were killed.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Five workers remained trapped roughly 1.5 km inside the tunnel for over 24 hours before rescue operations concluded.<\/span><\/li>\n<\/ul>\n<h2><b>Why the Explosion Occurred<\/b><\/h2>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Preliminary cause<\/b><span style=\"font-weight: 400;\">: Sudden explosive release of methane trapped or embedded in rock, likely ignited by drilling sparks.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>How methane accumulates in hills<\/b><span style=\"font-weight: 400;\">: It occurs as natural gas in porous rock or localised pockets in young, fragile geological formations \u2014 common in the Himalayan belt with historical coal-bearing strata. Oxygen-deprived, waterlogged hilly depressions and decomposing organic matter also generate methane.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Sikkim-specific geology<\/b><span style=\"font-weight: 400;\">: Though Sikkim has <\/span><b>no coalfields<\/b><span style=\"font-weight: 400;\">, it lies in the <\/span><b>Rangit Tectonic Window zone<\/b><span style=\"font-weight: 400;\">. Geological Survey of India studies found around 1.40 lakh tonnes of coal reserves in southern Sikkim, mainly in Namchi \u2014 the disaster site. A regional coal exploration project began there in December 2025.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Detection challenge: Methane is colourless and odourless. NHPC officials noted that standard tunnel surveys (topographical, geotechnical, geophysical, hydrological, resistivity, utility tests) cannot detect it.<\/span><\/li>\n<\/ul>\n<h2><b>Warning Signs Ignored<\/b><\/h2>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">A 2025 paper by five NHPC engineers, presented at an international geology conference in Croatia, documented repeated encounters with flammable gas, unstable rock, cavities, and heavy groundwater inflows during excavation.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Flammable gas was first encountered in November 2009 under original developer Lanco Teesta Hydro Power Ltd, causing a tunnel fire.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">After NHPC revived the project, methane was again detected seeping through an excavation face, with concentrations reaching nearly one-third of the lower explosive limit.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Workers alleged prior gas-related fires (six-seven months earlier) injured labourers, but no corrective action was taken; those who raised safety concerns faced job threats.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Workers also alleged safety equipment (helmets, safety shoes) was provided only during official inspections, and basic medical facilities like bandages were unavailable inside the tunnel.<\/span><\/li>\n<\/ul>\n<h2><b>Ecological and Regional Concerns<\/b><\/h2>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Environmental groups have long warned that extensive tunnelling and blasting across the Teesta basin could destabilise slopes and increase vulnerability to earthquakes and Glacial Lake Outburst Floods (GLOFs).<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">The October 2023 <\/span><b>South Lhonak GLOF<\/b><span style=\"font-weight: 400;\"> devastated the Teesta valley, destroying the Teesta III dam \u2014 reviving concerns about hydropower expansion in the basin.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">These groups have demanded fresh Environmental Impact Assessments for existing and proposed Teesta basin projects, arguing conditions have changed significantly since the GLOF.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Activists argue the tunnel blast is proof of long-ignored concerns that hydropower tunnels and reservoirs can generate methane, a climate concern beyond just safety.<\/span><\/li>\n<\/ul>\n<h2><b>Pattern of Himalayan Tunnel Disasters<\/b><\/h2>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Tunnelling risk is not isolated to Teesta VI. Notable prior incidents include:<\/span>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">Parbati-II Project, Himachal Pradesh (May 2021) \u2014 tunnel collapse killed 4 labourers<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">Subansiri Lower Hydroelectric Project, Arunachal-Assam border (June 2022, July 2024) \u2014 tunnel roof collapses killed workers<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">Khooni Nallah tunnel, Jammu-Srinagar highway (May 2022) \u2014 10 killed<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">Silkyara Bend-Barkot tunnel, Uttarakhand (November 2023) \u2014 41 workers rescued after cave-in<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">Srisailam Left Bank Canal tunnel (February 2025) \u2014 collapse trapped 8 engineers\/labourers<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">Tupul Railway Station, Manipur (June 2022) \u2014 landslip killed 61, India&#8217;s worst such disaster<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">Dhauliganga Hydroelectric Project, Uttarakhand (August 2025) \u2014 landslip; all 19 trapped NHPC employees rescued<\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h2><b>Conclusion<\/b><\/h2>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">The Teesta Stage VI tragedy is a grim convergence of fragile Himalayan geology, chronic project mismanagement, and disregarded worker safety warnings.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">It underscores the urgent need for updated environmental assessments, robust methane-detection protocols, and enforceable safety accountability before India expands infrastructure further into its most seismically and ecologically sensitive terrain.<\/span><\/li>\n<\/ul>\n<p><b>Source:<\/b> <strong><a href=\"https:\/\/www.thehindu.com\/news\/national\/sikkim\/what-caused-the-nhpc-tunnel-disaster-in-sikkims-namchi-explained\/article71252728.ece\" target=\"_blank\" rel=\"nofollow noopener\">TH<\/a> | <a href=\"https:\/\/theprint.in\/ground-reports\/sikkim-tunnel-blast-teesta-stage-vi-project-was-plagued-by-delay-and-debt-before-danger-struck\/2996482\/\" target=\"_blank\" rel=\"nofollow noopener\">TP<\/a><\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"<p>The Sikkim tunnel disaster highlights methane risks, worker safety failures, and the need for stricter environmental assessments.<\/p>\n","protected":false},"author":18,"featured_media":115270,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[18],"tags":[60,8975,22,59],"class_list":["post-115239","post","type-post","status-publish","format-standard","has-post-thumbnail","category-upsc-mains-current-affairs","tag-mains-articles","tag-sikkim-tunnel-disaster","tag-upsc-current-affairs","tag-upsc-mains-current-affairs-tag","no-featured-image-padding"],"acf":[],"_links":{"self":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts\/115239","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/users\/18"}],"replies":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/comments?post=115239"}],"version-history":[{"count":4,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts\/115239\/revisions"}],"predecessor-version":[{"id":115271,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts\/115239\/revisions\/115271"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/media\/115270"}],"wp:attachment":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/media?parent=115239"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/categories?post=115239"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/tags?post=115239"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}