Swapna Kumbar , Bengaluru - A groundbreaking NASA-ISRO satellite mission, NISAR (NASA-ISRO Synthetic Aperture Radar), has produced the most detailed maps yet of extreme land subsidence in Mexico City, revealing sinking rates up to several centimeters per month in key areas. Launched in July 2025 from India's Satish Dhawan Space Centre, NISAR's L-band radar pierced clouds and vegetation to capture ground motion between October 2025 and January 2026, confirming the city's decades long battle with groundwater depletion.

The vibrant heat maps show subsidence hotspots (in blue) concentrated east and northeast of the city center, where excessive aquifer pumping compacts soft lakebed sediments beneath the 22 million person metropolis. Rates exceed half an inch monthly in places, accumulating to fracture roads, tilt buildings, and rupture water mains over time. NISAR's dual frequency radar (L-band from NASA/JPL, S-band from ISRO) delivers millimeter precision deformation tracking every 12 days, unaffected by weather proving its value for urban planning and disaster preparedness. Mexico City's subsidence, among the world's worst, stems from its geological misfortune: built on an ancient lakebed drained for Spanish colonial expansion, now overexploited for water. Previous radar missions documented the trend, but NISAR's higher resolution and revisit frequency offer real time monitoring critical as climate change and population growth exacerbate risks.

NISAR's Mexico City maps validate the mission's promise for global change detection, equipping authorities with data to prioritize infrastructure reinforcement and sustainable water management. As subsidence accelerates, this US-India partnership demonstrates space tech's power to safeguard vulnerable megacities from silent, creeping disasters.