Ahmedabad: If you live in Thaltej, Bodakdev, Sarkhej, Lambha, or Baherampura, the ground beneath your feet is slowly sinking because of a human-induced phenomenon called land subsidence. You don’t feel subsidence because it happens slowly; it steadily creates conditions for a disaster.Land subsidence is the gradual settling of the earth’s surface. In cities built on soft, water-bearing soil, it happens when groundwater is extracted faster than it can be replenished. The soil compresses, and the ground above it gradually drops over the years, permanently damaging foundations, drainage systems, and underground infrastructure.Thaltej recorded the largest net shift of any ward studied — moving from 0.0313mm in 2016, meaning the ground was marginally stable, to a negative mean of -0.1121mm by 2025.What was stable ground nine years ago is now sinking ground, with a net change of approximately -0.1434mm over the study period — the most significant recorded across all wards.Bodakdev and Sarkhej, both western growth corridors that have seen some of the city’s most intensive construction over the past decade, were identified among the most affected zones, with significant negative displacement readings by 2025.Researchers group these western and southern corridors together as the city’s primary subsidence belt. Lambha, at the city’s southern edge, recorded what the researchers describe as the smallest net change among the wards studied.Its net shift was approximately -0.1174mm, moving from a 2016 mean of 0.0064mm to a 2025 mean of -0.1110mm.So why is this happening? Ahmedabad sits on layers of sand, silt, and clay deposited by the Sabarmati over centuries. As the city has grown, so has its demand for groundwater — for homes, industries, and agriculture.When water is extracted from underground, the fine-grained soil above it slowly compresses, like a sponge being squeezed dry. The result is what researchers call “deformation bowls” .Researchers at RV College of Engineering, Bengaluru — comprising Utkarsh Bharati, Chinmaya R, Mohit P L, Mohammed Haris, and Prof Ram Thilak — tracked Ahmedabad’s land movement between 2016 and 2025 using InSAR (Interferometric Synthetic Aperture Radar). The technique compares successive satellite radar images to measure ground shifts down to the millimetre.The team processed 21 satellite images from the European Space Agency’s Sentinel-1. The researchers note that the paper is not yet peer-reviewed and should be treated as “preliminary.”The research is titled “Land Subsidence Mapping of Ahmedabad and Kolkata Using InSAR” and was published on Elsevier’s SSRN platform.This is not a new finding for Ahmedabad. Research by the Institute of Seismological Research found that western and southeastern areas — including Bopal, Ghuma, and Vatva — were sinking at up to 25mm each year.
