For more than a century, Mexico City has been quietly disappearing — not into fire or flood, but into the earth itself. Now, for the first time, a revolutionary NASA-ISRO satellite called NISAR is capturing this slow-motion catastrophe in near real time, revealing that parts of the city are sinking by more than half an inch every single month.
14″Maximum sinking per year (35 cm)
20MPeople living on sinking ground
127 ftMax total sinkage recorded in worst-hit areas
What Is Happening to Mexico City?
Mexico City, home to over 20 million people, sits on one of the most geologically unstable foundations imaginable. The ancient Aztec capital of Tenochtitlán was originally built on an island in the middle of Lake Texcoco. When Spanish colonizers arrived in the 1500s, they drained the lake and built their city directly on top of the soft, waterlogged lakebed sediment left behind.
For hundreds of years, that decision seemed manageable. But as the city grew into one of the largest urban centers in the world, its appetite for freshwater grew with it. Beneath the city lies a vast underground aquifer — a layer of permeable rock and compressible clay saturated with water. To meet demand, water was pumped out of this aquifer at an enormous rate. The result? As the water drains away, the clay compresses and the ground above collapses. That process, known as land subsidence, is now one of the most severe urban geological crises on Earth.
“The houses that are founded in rock are stable, but the houses in the middle between the rock and the lacustrine plain are already broken, most of them. In 2017, a taxi fell inside a fracture.” — Dr. Dora Carreón-Freyre, geologist with 25+ years studying Mexico City’s subsidence
A Problem Over 100 Years in the Making
The sinking of Mexico City is not a new discovery. Engineer Roberto Gayol first reported on it in 1925, pointing to a large canal and drainage tunnel as a likely cause. By the late 1800s, the city was already subsiding at roughly two inches per year. But industrialization changed everything — by the 1950s, that rate had jumped to a staggering 18 inches per year in the worst-affected areas.
Today, scientists estimate that parts of the city have lost as much as 30 feet of elevation over the past century. In the hardest-hit zones, the total accumulated sinkage reaches as deep as 127 feet. The consequences are visible everywhere: cracked and buckled roads, tilting historic buildings, broken water mains, and a strained metro system constantly battling warped tracks and misaligned tunnels.
Perhaps the most striking symbol of the problem is the famous Angel of Independence monument on the Paseo de la Reforma. Since it was built in 1910, the ground around it has sunk so dramatically that 14 new steps have had to be added at its base — just to keep the entrance accessible at street level.
Enter NISAR: NASA’s Most Powerful Earth-Watching Radar Ever Launched
On July 30, 2025, NASA and the Indian Space Research Organisation (ISRO) launched a satellite that is changing how scientists understand our shifting planet. The NASA-ISRO Synthetic Aperture Radar — known as NISAR — is the first satellite in history to carry two different radar systems operating at different wavelengths simultaneously, and the results are extraordinary.
NISAR carries two radar instruments: an L-band radar built by NASA, operating at microwave frequencies of 1–2 gigahertz, and an S-band radar built by ISRO, operating at 2–4 gigahertz. The L-band is especially sensitive to changes in bedrock, land, and ice, while the S-band is tuned to detect changes in vegetation. Together, they give scientists an unprecedented dual-lens view of how Earth’s surface is moving.
The satellite’s radar antenna reflector is 39 feet (12 meters) across — the largest NASA has ever built. As NISAR orbits the Earth, it covers the entire surface of the planet every 12 days, building up a continuous, centimeter-precision record of surface movement. That level of regularity is what makes it so valuable.
“NISAR’s long-wavelength L-band radar will make it possible to detect and track land subsidence in more challenging and densely vegetated regions such as coastal communities.” — Craig Ferguson, NISAR Deputy Manager, NASA Headquarters
What NISAR Revealed About Mexico City
In May 2026, NASA released NISAR’s first detailed radar image of Mexico City — and it painted a sobering picture. The image, compiled from data collected between October 2025 and January 2026 (Mexico’s dry season), shows large swaths of the city shaded in deep blue, indicating areas that sank by more than half an inch (2 centimeters) in just that three-month window alone.
At that pace, the math is alarming. Half an inch per month translates to roughly six inches per year in those areas — and in the most affected zones, the rate climbs to 14 inches (35 centimeters) per year, a figure that has been documented for decades but can now be tracked with far greater precision and frequency than ever before.
Crucially, not every part of the city is sinking at the same rate, and that uneven movement is what causes so much structural damage. When one corner of a building sinks faster than another, the stress fractures walls, buckles floors, and breaks connecting infrastructure like gas lines and water pipes. NISAR’s data is now making it possible to map exactly which neighborhoods are most at risk — and at what speed.
Why Real-Time Monitoring Changes Everything
Before NISAR, scientists studying Mexico City’s subsidence relied on ground-based sensors or older space satellites that could only collect data annually. That meant a year-long blind spot between measurements — more than enough time for significant, undetected changes to occur.
NISAR’s 12-day revisit cycle transforms this. Scientists can now build what researchers call “time series” — sequential snapshots of how the ground is moving over time. This makes it possible to detect sudden accelerations in sinking, identify which engineering interventions are working, and model future risk with far more confidence.
For Dr. Dora Carreón-Freyre, who has spent more than 25 years walking the streets of Mexico City’s hardest-hit neighborhoods to study the damage by hand, the new satellite data is deeply emotional. “Things that we only learned by walking everywhere when we were young, it’s different now,” she said. “Technology is here to help us.”
Mexico City Is Just the Beginning
While Mexico City is an ideal test case — it is widely recognized as one of the fastest-sinking capitals in the world — the scientists behind NISAR are clear that this is only the opening chapter of what the satellite will reveal.
Land subsidence is a global crisis. Dozens of major cities around the world, from Jakarta and Manila to Houston and Venice, are sinking due to groundwater extraction, urban development, and climate change. In the Philippines, for example, researchers have recorded subsidence rates of up to 30 centimeters per year, compounded by the additional threat of rising sea levels — a dangerous double-burden that is threatening entire coastal communities.
“More broadly, my interest lies in mapping ground motion across coastal zones, where a large proportion of the world’s population lives,” said David Bekaert, a scientist on the NISAR mission. “Understanding surface change is particularly important” in those areas, he added, where subsidence and sea level rise often work together to amplify flood risk.
NISAR’s global, consistent coverage means no city has to wait for a targeted study to understand its risk. Every 12 days, the satellite silently sweeps over every coastal city, every wetland, every glacier, and every earthquake fault on Earth — recording changes down to a centimeter.
What Happens If Nothing Changes?
The trajectory for Mexico City, absent major intervention, is troubling. The primary driver of subsidence — groundwater extraction — remains deeply embedded in the city’s water supply infrastructure. Reversing it would require massive investment in alternative water sources, including surface water management and desalination, combined with aggressive groundwater recharge programs that pump treated water back into the aquifer.
Engineers and city planners also face the challenge of adapting existing infrastructure to the uneven ground. Buildings in many parts of the city have already been engineered to tolerate some movement, but as rates accelerate in specific zones and the cumulative sinkage deepens, the structural tolerances of older construction will eventually be exceeded.
The damage isn’t only physical. Broken water mains waste enormous volumes of the very resource that’s driving the problem. The Mexico City Metro — critical public transit for millions of daily commuters — faces ongoing disruption as subsidence warps rails and destabilizes tunnels. And in low-income neighborhoods like Iztapalapa, where the sinking is among the worst, residents live with broken streets and cracked homes that they often lack the resources to repair.
Frequently Asked Questions
Why is Mexico City sinking?
Mexico City was built on the drained bed of ancient Lake Texcoco. The city sits above a large underground aquifer made of soft, compressible clay sediment. Decades of pumping groundwater out of this aquifer has caused the clay to compress and the ground surface above it to sink — a process called land subsidence.
How fast is Mexico City sinking?
Different parts of the city are sinking at different rates. The average rate in affected areas ranges from a few inches per year to as much as 14 inches (35 centimeters) per year in the most severely impacted zones. Some areas have lost up to 30 feet of elevation over the last century, with the worst-hit spots recording total sinkage of up to 127 feet.
What is the NISAR satellite?
NISAR (NASA-ISRO Synthetic Aperture Radar) is a joint satellite mission launched by NASA and India’s ISRO on July 30, 2025. It is the first satellite to carry both an L-band and an S-band synthetic aperture radar, enabling it to measure changes in Earth’s surface with centimeter-level precision, covering the entire globe every 12 days.
Can Mexico City’s sinking be stopped?
Completely stopping the sinking would require ending or dramatically reducing groundwater extraction and finding alternative water supplies for 20 million people — a massive engineering and policy challenge. Slowing it, however, is possible through water management reforms, aquifer recharge programs, and stricter regulation of water use.
Is Mexico City the only city sinking like this?
No. Jakarta, Manila, Houston, Venice, and dozens of other major cities around the world are also sinking, many due to similar groundwater extraction. In coastal cities, this sinking is especially dangerous because it combines with rising sea levels to dramatically increase flood risk.