NHPC's own 2024 paper recorded gas fires in Teesta-VI tunnels before fatal blast

📌 Summary:

• A 2024 technical paper by NHPC's own engineers records that flammable gas, suspected to be methane, was encountered repeatedly and caught fire more than once inside the Teesta Stage-VI headrace tunnels in the years before the July 20, 2026 explosion that killed at least 15 workers
• The paper was authored by five NHPC engineers and presented at EUROENGEO 2024 (4th European Regional Conference of the International Association for Engineering Geology) in Dubrovnik, Croatia
• It documents the geological difficulties of completing the 500 MW project's two headrace tunnels, each about 13.7 km long
• The paper was written well before the accident and does not describe the recent blast — but shows the gas hazard was known internally, raising accountability questions about safeguards

🎯 UPSC Relevance: GS3 Disaster Management — foreseeability, institutional risk documentation and safety-governance gaps in large infrastructure projects.

📝 Prelims Facts:

• Teesta Stage-VI is a 500 MW hydroelectric project with two headrace tunnels ~13.7 km each
• The findings were presented at EUROENGEO 2024, Dubrovnik, Croatia
• The blast occurred on July 20, 2026, killing at least 15 workers

🔑 Key Term: Methane (CH4) — a colourless, odourless, highly flammable gas commonly trapped in fractured rock, a recognised hazard in underground tunnelling and mining.