Space-Time Evolution of Land Subsidence in India: Evidence for Recovery of Stressed Aquifer Systems

Groundwater is a critical resource that sustains life and livelihood on Earth. Changing climatic patterns and increased groundwater withdrawal to meet the demands of irrigation and municipal water supply have stressed the world’s major aquifer systems. Although groundwater is the largest available freshwater resource, it is often poorly monitored and hence poorly managed, particularly in data-scarce regions. Satellite-based Interferometric Synthetic Aperture Radar (InSAR) has emerged as a powerful tool for monitoring aquifer systems worldwide. In this study, we utilize nearly two decades (2007-2024) of InSAR measurements to investigate the temporal evolution of land subsidence in the Delhi National Capital Region of India. The observations revealed two major subsidence zones, located in the Dwarka (12 km²) and Gurgaon (1 km²) areas, with subsidence rates of up to 6.0 cm/year, which were observed between 2007 and 2010 in response to increased groundwater extraction. Post-2016, the subsidence zone near Dwarka began to show uplift (~2 cm/year) in response to rising groundwater levels. The areas north of Gurgaon, which had subsided by nearly 1m during 2014-18 at a rate of almost 15 cm/year, started to show a marked reduction in subsidence rate (from 15 cm/year to 7 cm/year) after 2019. Although these subsidence zones, located within the Administrative Boundary of Delhi (ABD), showed uplift/significant reduction in subsidence rate, Faridabad, a town outside the ABD, continued to subside till 2023. The rebound of the aquifer system and a substantial reduction in the subsidence rate are attributed to extensive groundwater management practices mandated within the ABD. The recovery of the stressed aquifer system, nearly 1.5 m after 2018, despite decreasing rainfall, further highlights the role of human intervention.