2.2.Existing downtowns to surrounding newly urbanized areas The downtowns of many cities in China are usually the areas with the densest population and the highest concentration of industries.They are also the areas with the greatest amounts of groundwater withdrawal. Therefore,land subsidence in each individual city has usually commenced from the downtown area of the city. In recent years,the implementation of controlling groundwater withdrawal in downtown areas has reduced the subsidence rate significantly.2.2. Existing downtowns to surrounding newly urbanized areas The downtowns of many cities in China are usually the areas with the densest population and the highest concentration of industries. They are also the areas with the greatest amounts of groundwater withdrawal. Therefore, land subsidence in each individual city has usually commenced from the downtown area of the city. In recent years, the implementation of controlling groundwater withdrawal in downtown areas has reduced the subsidence rate significantly