Land Subsidence Threat Overlooked

Tehran is losing the battle against land subsidence, as the earth sinks in some plains of the province by about 30 centimeters every year, and conditions are more critical in Shahriar and Varamin counties in southwest and south, director of the Forecasting and Early Warning Office at the Iran Meteorological Organization said.
“Annually, 31 centimeters of land subsidence are reported in Tehran Province. Over 3 billion cubic meters of water are extracted from groundwater sources in the capital every year,” ISNA also quoted Ahad Vazifeh as saying.
Land subsidence is defined as a gradual settling, or sudden sinking of the earth's surface owing to subsurface movement of earth materials. 
Its main causes are aquifer-system compaction, drainage of organic soils, underground mining, hydro-compaction, gas and oil extraction as well as earthquake.