A new global study has sounded the alarm over worsening land subsidence across India largest cities, revealing that excessive groundwater extraction is causing the ground beneath urban areas to sink posing grave structural and safety risks for millions.
Published in Nature Sustainability on October 28, 2025, the research warns that Delhi, Mumbai, Chennai, Kolkata, and Bengaluru are sinking at alarming rates, threatening more than 13 million buildings and nearly 80 million people.
Delhi Worst Affected
Among the five cities, Delhi recorded the highest subsidence rates up to 51 millimetres per year followed by Chennai (31.7 mm/yr), Mumbai (26.1 mm/yr), Kolkata (16.4 mm/yr), and Bengaluru (6.7 mm/yr). In the National Capital Region, the most affected zones include Bijwasan, Faridabad, and Ghaziabad where the land is sinking by as much as 38 mm per year.
Researchers attributed Delhi’s subsidence to the compaction of alluvial deposits caused by unregulated groundwater withdrawals. “The over-extraction of groundwater is compressing the soil layers beneath, leading to gradual but continuous land sinking,” the study noted.
Chennai Faces Fastest Deterioration After Delhi
In Chennai, subsidence is concentrated along the Adyar river floodplains and central neighbourhoods such as Valasaravakkam, Alandur, Kodambakkam, and Tondiarpet. The city’s alluvial and sandy soils make it particularly vulnerable. Two major hotspots K K Nagar and Tondiarpet show rapid land sinking linked to groundwater overuse.
Kolkata’s land movement is driven by the compaction of Pleistocene and Holocene sediments while Bengaluru’s relatively stable bedrock of granite and gneiss has limited the pace of subsidence so far. However, the city has seen increasing groundwater withdrawals since late 2022, heightening future risk.
Mumbai shows lower overall subsidence, except in informal, high-density settlements like Dharavi, where overuse of groundwater and weak soil conditions amplify vulnerability.
Millions of Buildings Face Structural Damage
The study estimates that 2,264 buildings in Delhi 110 in Mumbai and 32 in Chennai are already at high risk of structural damage due to uneven land sinking. Projections for the coming decades are even more dire: within 30 years as many as 3,169 buildings in Delhi, 958 in Chennai, and 255 in Mumbai could face severe damage.
By 2075, over 23,500 buildings across the five megacities may be at very high risk of collapse or structural instability with Chennai emerging as the most endangered in long-term projections.
Signs of Hope: Dwarka Rising Again
In a rare positive finding, the study identified localised uplift in parts of Dwarka, Delhi where the ground is rising by 15 mm per year an indicator of aquifer recovery. This rebound is credited to government regulations introduced between 2005 and 2011 that restricted borewell use, promoted rainwater harvesting, and revived traditional water bodies between 2012 and 2015.
Urgent Call for Policy and Regulation
The authors urged immediate mitigation and adaptation strategies to counter land subsidence. These include:
Strict groundwater extraction regulations
Enhanced aquifer recharge and rainwater harvesting
Improved surface water management
Urban re-vegetation and soil conservation
Experts caution that without urgent intervention, unchecked urbanisation and groundwater depletion could turn India megacities into long-term geological hazards.
The findings serve as both a warning and an opportunity to rethink water management, enforce stricter regulations, and ensure India’s cities don’t sink under the weight of their own growth.