A seismic decision: On revision to India’s earthquake zoning, rollback

The Centre’s rollback of the revision to India’s earthquake zoning by the Bureau of Indian Standards (BIS), follows a major challenge to the methodology used, which some engineers believe are out of sync with site-based evaluations. Yet, the reversal is driven largely by the massive cost and execution implications, as the decision impacts urban planning, disaster preparedness and climate resilience. The current earthquake zoning exercise is an opportunity to disaster- and climate-proof cityscapes, power infrastructure, dams, highways, and homes and offices as India undertakes an urban infrastructure expansion. Getting the zoning framework right has, arguably, never been more important.

At the heart of the debate lies the scientific approximation of possible earthquakes and their intensities, vis-à-vis the preparedness of the built environment to withstand them. Globally, most advanced economies and seismically active regions now use Probabilistic Seismic Hazard Assessment (PSHA), a dynamic framework that models earthquake risk through probability-based simulations of ground motion. Until now, India has primarily used a simpler fixed zoning model. The BIS’s attempt to move toward this globally accepted framework is, therefore, directionally correct. However, some structural engineers and policymakers argue that the revisions, which were notified in November 2025 and withdrawn on March 3, were too stringent. The proposed framework introduced an entirely new top-risk category, Zone VI, covering most of Kashmir, parts of the Himalayan belt, Kutch in Gujarat and the north-east. Urban planners worry that such zoning could stall developmental and infrastructure activity in already economically fragile regions, and potentially push more housing into the informal sector — which already accounts for nearly 80% of India’s homes. Estimates suggest that a one-zone increase could raise costs by around 20%, and two zones by nearly one-third. For major infrastructure such as metro rail systems, dams and power stations, the cost implication could be significantly higher. Pushback to the BIS revisions has come from both the private sector and within government, including the Ministries of Housing and Urban Affairs, Home Affairs, the Central Water Commission and the National Dam Safety Authority. Another layer in this debate is climate. The construction sector in India is among its largest dispersed sources of carbon emissions. While a revision in the earthquake zoning framework is necessary, it requires wider consultation across ministries, regulators and industry stakeholders. Only a holistic and implementable framework can strengthen disaster resilience and address climate mitigation, affordability and execution challenges.