How decades of growth are making Ho Chi Minh City sink faster than ever

Research published in Nature Sustainability by experts from Singapore's Nanyang Technological University, NASA and the Swiss Federal Institute of Technology found the southern Vietnamese metropolis to be one of the world’s most rapidly subsiding cities. Local studies show parts of the city have sunk by more than 23 centimeters between 2005 and 2017, with some "subsidence funnels" lowering at a rate of over 10 centimeters per decade.

The problem is rooted in both natural and human causes. Ho Chi Minh City sits atop soft, compressible Holocene sediments, a young river delta made of clay, silt and peat that easily deforms. Seasonal tides, saltwater intrusion and groundwater fluctuations further weaken the ground, particularly in the southern districts of 7, 8, Nha Be and Binh Chanh.

Before 2010, nearly 60% of the city’s water supply came from underground wells. Unchecked drilling across outlying districts, including Binh Chanh, Hoc Mon, Cu Chi and Nha Be, left vast cavities below ground, accelerating the city’s gradual collapse. In 2010, authorities recorded over 200,000 private wells, extracting more than one million cubic meters of water daily, five times the approved limit.

Although regulations since 2012 have curbed drilling and aimed to cut groundwater extraction to 100,000 cubic meters a day by 2025, the city continues to sink.

"Subsidence is a cumulative process. Even if groundwater use falls, the ground keeps settling for years," said Le Song Giang of Ho Chi Minh City University of Technology.

Urbanization has compounded the issue. The city’s rapid growth, with urbanization rates reaching 80% during 2011–2017, has paved over natural soil with concrete and asphalt, blocking rainwater from replenishing underground aquifers. Heavy traffic and skyscraper construction further compress the ground, worsening subsidence in low-lying zones like South Saigon, Thanh Da Peninsula, Thao Dien and Hiep Binh Phuoc along the Saigon River.

To adapt, experts urge the creation of a permanent subsidence monitoring network, stronger foundation standards for new buildings and the integration of green and blue infrastructure: water parks, retention lakes and wetlands that double as drainage basins during the rainy season.

"Subsidence isn’t a death sentence for a city," said Nguyen Hong Quan from Vietnam National University. "Even places like Venice still live with it. The key is understanding the causes early, collecting data, and planning accordingly."