Building damage risk in sinking Indian megacities

Building damage poses serious safety risks, causing substantial financial losses worldwide. Engineering shortcomings are commonly cited as the cause of long-term structural failures, often neglecting the exacerbating role of land subsidence. Here we used satellite radar observations during 2015–2023 to estimate differential settlements at 5 fast-growing Indian megacities, including more than 13 million buildings and 80 million people. Our analysis reveals 878 km² of land subsiding, exposing ~1.9 million people to subsidence rates of more than 4 mm yr−1. An estimated 2,406 buildings across Delhi, Mumbai and Chennai are at high risk of structural damage from ongoing land subsidence. Sustained over 50 years, current subsidence rates could place as many as 23,529 buildings at very high risk of structural damage in Chennai, Delhi, Mumbai, Kolkata and Bengaluru. Our results highlight the compounding risk of infrastructure damage from subsidence, assisting policymakers to develop resilience plans and adaptation strategies that prioritize mitigation and maintenance spending. Building damage and collapse is an emerging problem, particularly in large cities in developing countries. Although engineering shortcomings are often blamed, land subsidence is an underappreciated culprit that could put tens of thousands of buildings at risk across Indian megacities.