Science
NISAR: The India-US Radar Satellite Showing Mexico City Sink Into the Ground
A city of 22 million people is slowly sinking — and a joint Indian-American space mission just captured the clearest map yet of how fast it's happening. The NISAR satellite, built by ISRO and NASA together, revealed some neighborhoods are dropping by more than 40 centimetres a year.
40 cm/yearMaximum ground sinking rate recorded in parts of Mexico City by NISAR
The facts
- 1NISAR (NASA-ISRO Synthetic Aperture Radar) is a joint satellite mission between India's ISRO and the US space agency NASA, launched in 2025 to study Earth's surface using powerful radar.
- 2Mexico City is built on a former lakebed filled with soft, water-saturated clay, which compresses and sinks as groundwater is pumped out — a process called subsidence.
- 3NISAR's data shows parts of Mexico City sinking by over 40 centimetres (roughly the length of a school ruler) every single year, among the fastest rates ever recorded for a major city.
- 4The satellite uses synthetic aperture radar (SAR), which can measure ground movement to within a few millimetres even through clouds or at night — something ordinary cameras cannot do.
- 5Scientists at NASA's Jet Propulsion Laboratory used NISAR data captured between October 2025 and April 2026 to produce the detailed subsidence map now being studied by city planners.
Why it matters
If the ground keeps sinking unevenly, buildings crack, water pipes burst, and flood risk rises sharply. Mexico City's challenge is shared by many cities — including parts of Chennai and Mumbai — built on soft or reclaimed ground. Missions like NISAR show how space technology can give city planners early warnings before damage becomes catastrophic.
Sources
- NASA Jet Propulsion Laboratory
- ISRO (Indian Space Research Organisation)
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