The ground under Medan, Indonesia, sank by a median of 32.7 millimeters a year from 2014 to 2023, the fastest rate among 465 large cities measured by satellite in a study published Oct. 12 in Nature Cities by researchers at Peking University. Over those nine years that adds up to about 294 millimeters, nearly a foot, and the pace is more than seven times the 4.5 millimeters a year the global ocean rose in 2023, according to NASA.
The study covers every city of more than 1 million people where the satellite data was clear enough to measure, across 107 countries. The hottest spots on the globe below are Medan and Bandung in Indonesia, Torreón and Mexico City in Mexico, and Isfahan in Iran.
Touch the globe to spin it, and tap any city to see how fast its ground is moving.
Sinking is common, though rarely at Medan's pace
The ground at the median point moved down in 409 of the 465 cities, about 88%. Most of that sinking is slow, and 281 cities sank less than 1 millimeter a year or rose. Only 27 cities sank faster than the sea is rising, and 12 of them are in China, more than in any other country. Bandung, at 21.9 millimeters a year, was second to Medan, followed by Torreón, Mexico, at 17.3 and Isfahan, Iran, at 10.6.
A foot of lost ground is hard to picture from a rate, so the chart below shows nine years of it. Press play to watch each city's ground drop, with the blue line marking how much the sea rose over the same span.
Mexico City's worst ground sinks 27 times faster than its median
Mexico City's citywide median of 7.9 millimeters a year ranks eighth, but no city in the study has a more extreme fast-sinking zone. Its fastest-sinking 5% of ground dropped at least 216.5 millimeters a year, about 27 times the city's median and well beyond the next-worst city on this measure, Semarang, Indonesia, at 151.4. Over nine years, 216.5 millimeters a year adds up to about 1.95 meters, or 6.4 feet, more than the height of most adults.
About 46.5% of Mexico City's measured area sank faster than 10 millimeters a year, more than twice the share in Houston and over 100 times the share in Seoul. Sinking that uneven pulls on pipes, rail lines and foundations, since one part of a building can drop faster than another.
Houston is the only big U.S. city sinking faster than the sea
Houston's ground sank 4.8 millimeters a year, ranking 24th of 465 and putting it just above the sea's 4.5 millimeters. None of the study's other 49 U.S. cities sank more than 2 millimeters a year: San Bernardino was next at 2.0 and Fort Worth at 1.6, while New York sank 0.4 and Boston rose 0.1. In Houston, 21.1% of the city's area sank faster than 10 millimeters a year, compared with 1.1% in New York.
Search for your city below. It opens on Houston, and picking any city also spins the globe above to it.
Why the ground drops
The authors found faster sinking in cities in developing countries than in developed ones, a difference they report as statistically significant, and they point to pumping groundwater out of the soil beneath cities as a main cause. When water is drawn from clay layers faster than it is replaced, the clay compacts and the surface settles. Sinking can be slowed, too: Beijing, whose median rate was 1.9 millimeters a year, began refilling its aquifers around 2016, and the authors found that sinking had stopped in several parts of the city afterward. They also found sinking slowing in many cities in Southeast and East Asia, even as large areas of those same regions were still speeding up.
How we measured: City rates are from Lijun Wang, Shengli Tao, Xie Hu and colleagues, "A global view of urban land subsidence and its changing trajectories," Nature Cities, Oct. 12, 2026, which used Sentinel-1 satellite radar (InSAR) from June 2014 to June 2023 for 465 cities of more than 1 million people in 107 countries. We used the authors' published figure data: each city's median rate of relative local land subsidence, the 5th-percentile rate (its fastest-sinking 5% of ground) and the share of its area sinking faster than 10 millimeters a year. Rates are measured relative to a reference point inside each city, so they show local sinking and not motion of the whole region. Nine-year totals multiply each rate by nine. The sea-level comparison uses NASA's measured rate of global mean sea-level rise in 2023. Nature Cities study. Authors' data. Authors' city maps. NASA sea-level rate. Download our data (CSV).