Two years before the tunnel gave way, five of NHPC's own engineers stood at a conference in Dubrovnik and read out, in careful technical language, exactly how this could happen.

The Difference Between a Risk and a Warning

An explosion inside NHPC's Teesta Stage-VI tunnel in Sikkim has killed 22 workers and the instinct - India's and NHPC's own initial framing - has been to treat this as a tragic collision with unpredictable Himalayan geology.

Methane pockets, after all, are a genuine hazard of tunnelling through young, fractured, seismically active rock. But that framing survives only until you read what NHPC's own engineers wrote two years before the blast.

What the

record actually shows In 2024, five NHPC engineers presented a technical paper at EUROENGEO in Dubrovnik describing, in granular detail, the geological difficulties of excavating Teesta-VI's headrace tunnels. The paper records that flammable gas was first detected as far back as 2009, that it recurred at the contact zone between hard quartzite and carbon-rich phyllite and that it had caught fire more than once inside the tunnel faces designated 4A and 4B - both reached through Adit-3, the exact access point where the July blast occurred.

This was not a hidden hazard waiting to be discovered. It was a documented, named, located risk, published by the company's own personnel, sitting in the technical literature for two years before it killed anyone.

Why this changes the question The honest question after a geological disaster is usually "could this have been foreseen?" Here, it already was - by the people best positioned to know.

So the real question shifts: was this risk carried into project planning and translated into gas-detection and ventilation safeguards proportionate to what the paper described? Or did institutional knowledge simply sit in a conference proceeding, disconnected from the environmental-clearance conditions and safety protocols actually enforced on site?

NHPC restarted excavation only in 2021, after nine idle years during which earlier tunnel sections had collapsed and adits had flooded - a restart under pressure, on a stalled asset, is precisely the setting in which documented risk and enforced practice tend to drift apart.

Where the

balance should sit Himalayan hydropower is not, on the strength of this disaster alone, a case that should be abandoned - the region's energy needs and the strategic logic of harnessing its river systems remain real. But the case for continuing does not extend to continuing on the current terms of self-certified risk management.

When the operator's own published research anticipates the failure mode that later kills workers, the fault is not geology; it is the absence of an independent mechanism that could have forced that paper's findings into binding safety practice before excavation resumed.

Environmental clearances for Himalayan infrastructure need a condition that does not currently exist in practice: mandatory third-party verification that documented geological hazards have been translated into engineering safeguards, checked before work restarts, not audited after workers die.

That is a narrower, more defensible demand than a moratorium - and precisely because NHPC's own paper proves the risk was knowable, it is a demand this disaster has earned.