WStep into the vast heart of Mexico City pedestal It’s a dizzying experience. At the edge of the square, the capital’s cathedral, with its towering spire, leans in one direction. The attached church, known as the Metropolitan Sanctuary, leans to the opposite side. The nearby National Palace also seems unusual.
The teetering of many of the capital’s historic buildings is the most visible sign of a phenomenon that has been going on for more than a century. Mexico City is sinking at an alarming rate.
Now, one of the most powerful radar systems ever launched into space is tracking the metropolis’ descent in real time. The satellite, known as Nisar, can detect minute changes in the Earth’s surface even when covered by thick vegetation or clouds.
“Nysar takes radar imaging observations of Earth to the next level,” said Marin Govortin, a scientist at NASA’s Jet Propulsion Laboratory. “Nisar allows us to observe all the changes, big and small, that occur on Earth every week. No other imaging mission can claim this.”
Buildings affected by land subsidence. Photo: Ross D. Franklin/AP
This is not the first time Mexico City’s subsidence has been observed from space, but the Nisar probe was able to better determine how widespread the subsidence is and how it changes across different land types than other space-based sensors. They have also been able to penetrate areas on the outskirts of cities that were previously difficult to study due to their complex topography.
The meaning of the image extends far beyond Mexico’s capital. “This study on Mexico City speaks to the realm of possibilities that opens up thanks to the Nisar system,” said Dario Solano Rojas, an engineer at the National Autonomous University of Mexico (Unam). “And it’s useful not only for sinking cities, but also for studying volcanoes, studying deformation associated with earthquakes, and studying landslides.”
Subsidence map of Mexico City using data from the Nisar mission from October 2025 to January 2026. Dark blue indicates areas found to be sinking more than 2 cm per month. Photo: NISAR
NASA says the technology can also monitor the climate crisis, glacier slides, agricultural productivity, soil moisture, forests, coastal flooding, and more.
“Images like this are just the beginning,” says David Bekaert, project manager at Flanders University of Technology and member of the Nisar science team. “There will be an influx of new discoveries from all over the world.”
The Nisar system, a joint initiative between NASA and the Indian Space Research Organization, found that some areas, including Mexico City’s main airport, are sinking more than two centimeters per month, one of the fastest sinking rates in the world.
One of the clearest examples of this rapid descent is the Statue of the Independent Angel on the city’s main Reforma street. Built in 1910 to commemorate Mexico’s 100th anniversary of independence, this 36-meter-tall monument had 14 steps added to its base as the surrounding land gradually subsided.
Former Mexican soccer player Diego Ivan Carmona appeared in front of the Angel of Independence statue in Mexico City last month. Photography: Yuri Cortes/AFP/Getty Images
But the effects of Mexico City’s subsidence are felt throughout the metropolis of about 22 million people, from leaning buildings to distorted roads and damaged underground subway systems.
“It will affect the entire urban infrastructure of the city: roads, water pipes, water pipes, drainage pipes,” said Efrain Obando Sherry, another Unum engineer.
First recorded in 1925, the city’s subsidence is the result of centuries of groundwater exploitation. Mexico City and its surrounding areas were built on an ancient lakebed, so the soil beneath the city is very soft. As water is pumped from underground aquifers, this clay-like soil is compacted, resulting in a silently sinking city.
“Mexico City is sinking primarily because groundwater is being pumped out of the aquifer beneath the city at a rate that far exceeds natural recharge through precipitation. As water is withdrawn, the aquifer is compressed under the weight of the city above it,” Govorchin said.
In 2016, a tour guide pointed out the unevenness and subsidence of buildings in Templo Mayor. Photo: Ross D. Franklin/AP
Underground aquifers still account for about half of the capital’s water supply. Aquifer shrinkage has intensified as groundwater extraction increases, and the water table is currently shrinking by about 40 cm per year.
This creates a vicious cycle. As the city sinks, the aging pipes that pump water into the city center crack and break, resulting in the loss of an estimated 40% of the capital’s water to leaks. Add to that the climate crisis, with years of low rainfall, and large cities may be heading toward a disaster scenario in which water supplies run dry in some parts of the city.
When it comes to the slow decline of cities, there are limited efforts to address this problem beyond strengthening the foundations of ancient buildings. Experts say images of Nisar will help draw attention to the problem, but actually stopping its descent will be a difficult task.
“To stop the subsidence, we also have to stop the water intake,” Shelley said. “So what kind of water are we going to drink if we stop harvesting water? The classic joke is if you can’t drink water, drink tequila.”
