A drought in Iran is causing the ground to subside, threatening Tehran and hundreds of other towns.

More than 800 towns and villages, including the capital Tehran and the major city of Isfahan, are at risk from land subsidence, Iranian authorities say.

The ground beneath Tehran sinks by up to 22 centimeters (around 9 inches) every year, which is seven times higher than what would be normally expected.

The reason, experts say, is the country’s acute water shortage.

“This is a serious crisis affecting at least half of Iranian society,” said Roozbeh Eskandari, a Canadian-based expert on a hydraulic structures and dam construction.

Eskandari has long since warned about the consequences of Iran’s water scarcity.

“Land subsidence resulting from unsustainable water consumption endangers the country’s entire infrastructure, including pipelines, power lines and railroads,” Eskandari told DW.