Questions Beneath the Surface: On the Sikkim Hydroelectric Disaster
India is currently facing another tragic incident in its Himalayan region. At the Teesta Stage-VI hydroelectric project, managed by NHPC Limited (previously National Hydroelectric Power Corporation Private Ltd.), in Sikkim’s Namchi district, workers in a tunnel under construction encountered what is believed to be a pocket of trapped methane gas. The subsequent explosion caused significant damage to parts of the tunnel, resulting in the deaths of at least 15 of an estimated 25 workers, with search and rescue operations still active. NHPC has announced its intention to conduct a thorough investigation. Methane is a well-understood danger in underground excavation, and the geological conditions of the Teesta basin make its presence particularly probable. This basin lies in an area prone to seismic activity, characterised by young, highly fractured rock formations where compressed gas pockets, formed long ago, can remain concealed until excavation work disturbs them. Therefore, the mere presence of the gas itself is not entirely unexpected. However, what remains unclear, and is far more critical, are the precise circumstances under which this gas pocket was breached, whether its risks were properly assessed and factored into the project’s planning, and if the necessary gas-detection and ventilation safety systems for such conditions were correctly installed and operational.
Subterranean construction in India’s challenging terrain has consistently been fraught with danger. Earlier this year, in February, a fatal blast at an unauthorised coal mine in Meghalaya claimed the lives of approximately 30 workers. In 2023, a section of a road tunnel being built in Uttarakhand collapsed, trapping 41 workers for 17 days before their successful extraction. These incidents, while differing in their specifics, collectively highlight the persistent and deadly risks associated with underground and tunnelling work across the nation. A series of hydropower developments spanning the 400-kilometre course of the Teesta River, which connects Sikkim, West Bengal, and Bangladesh, possess varied histories concerning environmental approvals but share a fundamental characteristic: their location within the delicate Himalayan environment. This inherent vulnerability was tragically demonstrated in October 2023, when a glacial lake outburst flood originating from the South Lhonak lake led to the destruction of the Teesta-III dam and caused over a hundred fatalities downstream. Teesta-VI itself was taken over by the public-sector NHPC Limited after its original private developers declared insolvency, unable to manage escalating expenses. While immediate relief and rescue efforts must be the top priority, and every measure to reach those still trapped is justified, once this emergency phase concludes, the government cannot afford to view this disaster as an isolated misfortune. It is imperative that an exhaustive, independent investigation is commissioned to determine whether the conditions stipulated in the project’s environmental clearance were, in practice, rigorously adhered to.