Parts of Mexico City are dropping at rates that surprised even the scientists watching from space. A joint US-Indian satellite mission has measured land sinking as fast as 1.6 inches per year in some neighborhoods, a pace that threatens buildings, water pipes, and the daily lives of millions.
A City Built on a Drying Sponge
Mexico City sits on an ancient lakebed. The soft clay beneath it once floated on water. For decades, residents and industries have pumped groundwater out of the aquifer below, and as the water disappears, the ground compresses and sinks. This process, called subsidence, is not new. But the new data from the NISAR satellite, a collaboration between NASA and the Indian Space Research Organisation, shows just how uneven and extreme the sinking has become.
Where the Ground Is Giving Way
The satellite mapped the entire metropolitan area from orbit between February and April 2025. It found that some central and eastern districts are dropping more than an inch per year. In the worst spots, the land falls by more than four inches annually. Meanwhile, other parts of the city remain relatively stable. That uneven sinking puts stress on infrastructure: subway lines bend, roads crack, and sewer systems lose their slope, causing backups and flooding.
Local authorities and urban planners have long known the city is subsiding, but they lacked this level of detail. The NISAR data gives them a block-by-block picture of where the ground is moving fastest. That matters because Mexico City is home to over 21 million people. When the land sinks unevenly, the damage is not just cosmetic, it can make buildings unsafe and strain the water system that is already struggling.
Why This Matters Beyond Mexico
The mission is a joint effort between the United States and India, and its findings in Mexico City are a proof of concept. NISAR is designed to monitor Earth’s surface globally, tracking changes in ice, forests, and ground movement. The same technology that spotted subsidence in Mexico can be used to detect sinking in other cities around the world, from Jakarta to Venice to Tokyo, where groundwater pumping is causing similar problems.
For now, the data offers Mexico City something it has never had: a precise, up-to-date map of where the ground is falling fastest. Whether that leads to policy changes or engineering fixes is up to local leaders. But the satellite has done its job. It has shown, in vivid detail, that the ground beneath millions of feet is moving, and it is not stopping.
