India’s largest cities are sinking, which may lead to a future catastrophe, according to Virginia Tech scientists who caution that millions of lives and thousands of buildings in densely packed urban areas are at risk.
With over a third of the residents of the most populous nation on Earth living in cities, and that percentage expected to continue growing, India’s destabilized urban infrastructure is a significant concern. The primary catalyst for the sinking is groundwater overuse as municipalities struggle to provide enough water for expanding populations, according to a recent paper published in Nature Sustainability.
Observing Urban Sinking
“When cities pump more water from aquifers than nature can replenish, the ground quite literally sinks,” said co-author Susanna Werth. “Our study shows that this overexploitation of groundwater is directly linked to structural weakening in urban areas.”
The team measured subsidence, or differential ground sinking, in five major Indian cities over the last decade: New Delhi, Mumbai, Chennai, Kolkata, and Bengaluru. To do so, they analyzed satellite radar data collected between 2015 and 2023 for these urban centers, which together house roughly 80 million people and 13 million buildings.
Based on the team’s results, 339 square miles of land are sinking between these cities. Almost 1.9 million people reside in areas experiencing subsidence rates exceeding 4 millimeters per year. Between just New Delhi, Mumbai, and Chennai, the paper estimates that approximately 2,406 buildings face a high risk of structural damage. Extrapolating from these trends over the past decade, the number of at-risk buildings could reach more than 23,000 within the next 50 years.
Combined Catastrophe
With climate change driving increased weather turbulence, India’s high rate of urban subsidence takes on even greater risks. Earlier this year, northern India experienced flash floods and overflowing rivers that claimed lives and submerged essential farmlands. According to India’s National Disaster Management Authority (NDMA), 59% of the country’s land is under moderate to severe threat from seismic events.
Adding subsidence to the country’s ongoing flood and earthquake concerns compounds the issues, as uneven sinking increases structural vulnerability by weakening foundations and damaging utility lines.
“The silent strain we see today could lead to tomorrow’s disasters if cities do not adapt their infrastructure and groundwater management policies,” said lead author Nitheshnirmal Sadhasivam, a graduate student working with Werth.
Identifying Future Urban Threats
The new work provides a strong framework for applying satellite data to mitigate future disasters. While keeping an eye on the problem is necessary to determine its scope, much more concrete actions will be required to avoid a catastrophe.
“Our research shows how satellite-based ground mapping techniques can reveal risks that are otherwise hidden until collapse occurs,” said co-author Manoochehr Shirzaei. “Investing in adaptation now, through groundwater regulation, resilient design, and proactive monitoring, will save lives and resources in the long run.”
With increasing urbanization globally, following a shift toward manufacturing and information jobs in traditionally agricultural economies, India is not the only country facing this issue. A 2024 study found that half of China’s cities are also sinking, noting that subsidence-related disasters had already incurred 7.5 billion yuan in damages.
With global cooperation frayed and climate threats looming, resolving the oncoming crisis will be no easy feat. Already stressed aquifers are being pushed to the limit to meet the needs of rapid expansion. As the issue stands presently, these infrastructure dangers are set only to grow in the coming decades.
The paper, “Building Damage Risk in Sinking Indian Megacities,” appeared in Nature Sustainability on October 28, 2025.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.