Environment

Tehran Is Sinking

The ground is shifting under Iran's capital, Tehran, home to approximately 15 million people and the biggest city by population in western Asia. High-resolution satellite images recently revealed that in some places, the metropolis of the Middle East is sinking about 10 inches (25 centimeters) per year.

researchers found Tehran's current subsidence rate to be among the highest in the world, with groundwater loss driven by drought, dam construction and a booming population. Another troubling discovery was that rainfall wasn't replenishing depleted groundwater reserves, suggesting it may already be too late for the land to recover.

Tehran isn't the only sinking city. Satellite observations have also shown that Venice, Italy; parts of western Texas and coastal Louisiana; California's San Joaquin Valley and San Francisco International Airport are victims of subsidence.

Should the sinking continue, Tehran's railways, bridges, gas and oil pipelines, and electrical infrastructure could be at risk