Mexico City’s historic Zócalo plaza offers a stark visual of the capital’s sinking problem, but the cathedral, the Metropolitan Sanctuary, and the National Palace all appear tilted in different directions. This is a visible sign of a long-term phenomenon: the city is slowly sinking into the ground.

Nasa’s Nisar Satellite Monitors Subsidence

One of the most powerful radar systems in space, Nasa’s Nisar satellite, is now tracking Mexico City’s descent in real time — the satellite can detect even minor changes in Earth’s surface, including through dense vegetation and cloud cover.

“Nisar takes radar imaging observations of Earth to the next level,” said Marin Govorčin, a scientist at Nasa’s Jet Propulsion Laboratory, while “Nisar will see any change big or small that happens on Earth from week to week. No other imaging mission can claim this.”

Implications for Global Research

Though Mexico City’s sinking has been studied before from space, the Nisar mission provides more detailed insights into how the subsidence spreads and how it varies across different types of land. The satellite has also been able to penetrate areas on the outskirts of the city that were previously difficult to study due to the complex terrain.

“This study of Mexico City speaks to the area of possibilities that will open up thanks to the Nisar system,” said Darío Solano-Rojas, an engineer at Mexico’s National Autonomous University (Unam). “And not just for sinking cities but also for studying volcanoes, for studying the deformation associated with earthquakes, for studying landslides.”

According to Nasa, the Nisar satellite can also monitor the climate crisis, glacier sliding, agricultural productivity, soil moisture, forestry, coastal flooding, and more.

“Images like this are just the beginning,” said David Bekaert, a project manager at the Flemish Institute for Technological Research and a member of the Nisar science team. “We’re going to see an influx of new discoveries from all over the world.”

Subsidence Rates and Urban Impact

Some areas of Mexico City. Including the main airport. Are sinking by more than 2cm a month—among the fastest subsidence rates globally. The Angel of Independence statue on Paseo de la Reforma, built in 1910, has had 14 steps added to its base as the land around it has sunk gradually.

The impact of the subsidence extends beyond the skyline, Across the metropolis of about 22 million people, the effects include tilting buildings, warping roads, and damage to the underground metro system.

Efraín Ovando Shelley, another engineer at Unam, explained: “It affects the entire urban infrastructure of the city: the streets, the pipes for water distribution, the water supply, the drainage pipes.”

First documented in 1925. The city’s sinking is a result of centuries of groundwater exploitation; the region was built on an ancient lake bed, and the soil beneath is extremely soft. When water is pumped out of the aquifer below, the clay-like earth compacts, causing the city to sink quietly over time.

Govorčin added: “Mexico City is subsiding primarily due to pumping of groundwater from the aquifer below the city at a rate that far exceeds natural recharge from precipitation. As water is withdrawn. The aquifer compacts under the weight of the city above it.”.

The underground aquifer still provides about half of the capital’s water supply. As groundwater pumping has increased, the aquifer’s shrinking has intensified, with the water table now contracting by about 40cm a year.

This creates a vicious cycle: as the city sinks, the aging water pipes become cracked and broken, with the capital losing an estimated 40% of its water due to leakage. Combined with the climate crisis,marked by years of low rainfall,the metropolis may be heading toward a disaster scenario in which taps in large parts of the city run dry.

Experts say the Nisar imagery will help draw greater attention to the issue, although halting the descent will be a difficult task.

“To stop the sinking, we would have to stop water extraction,” Shelley said. “And if we stop water extraction, what water are we going to drink? The standard joke is that if we can’t drink water, well, let’s drink tequila.”