Mexico City is sinking rapidly, Nasa warns—and it’s part of a global subsidence crisis

One of the world’s largest metropolises is quite literally folding in on itself.

New satellite data released by the Nisar mission, a joint venture between Nasa and the Indian Space Research Organization (Isro), has confirmed that parts of Mexico City are subsiding at a rate of up to 20 inches (50 cm) per year.

For a city of 22 million people built atop the ancient, clay-rich lakebed of Lake Texcoco, the situation has moved beyond a geological curiosity to a full-scale structural emergency.

A century of sinking

The primary culprit is groundwater over-extraction. As the city pumps water from underground aquifers to meet the demands of its massive population, the soft clay layers beneath the surface compress. Once this clay collapses, it can never regain its original volume, making the subsidence permanent and irreversible.

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Mexico City is not alone in its descent. Across the globe, rapid urbanization and climate change are forcing major cities into a battle against gravity.

While Venice is often the "poster child" for sinking cities, its rate of descent is glacial compared to Mexico City or Jakarta. In Indonesia, the crisis is so severe that the government is physically relocating its capital to Nusantara on the island of Borneo.

The Indian crisis

India is facing its own localised version of this catastrophe in the Himalayan town of Joshimath. While Mexico City sinks due to water loss in clay, Joshimath is sliding due to its placement on 7,000-year-old glacial debris.

In 2023, the town grabbed global headlines when deep fissures tore through over 800 homes. Experts from the Wadia Institute of Himalayan Geology warn that the ground is still moving. Unlike Mexico City’s uniform drop, Joshimath suffers from slope instability, where heavy monsoon rains lubricate the loose debris, threatening to bring the entire town down into the Alaknanda River.

From the “Angel of Independence” in Mexico City now needing 14 extra steps to reach street level to the cracked temples in Joshimath, the pattern is hard to miss. In both places, rapid human expansion is pushing the limits of what the ground beneath can handle.