One recent study found that Iran’s central plateau, where most of the country’s aquifers are located, is sinking by more than 35 centimeters each year. As a result, the aquifers lose about 1.7 billion cubic meters of water annually as the ground is permanently crushed, leaving no space for underground water storage to recover, says Darío Solano, a geoscientist at the National Autonomous University of Mexico, who was not involved with the study.