More than 50 cities in China have wide-spread land subsidence, China Central Television (CCTV) reported Monday.

As large as 79,000 square kilometers of land has dropped more than 200 millimeters, Zhang Zuozhen, vice-president of China Geological Environmental Monitoring Institute, told CCTV.

The subsidence mainly occurs at the Yangtze River Delta, North China and plain areas covering North China's Shanxi province and Northwest China's Shaanxi province, he said.

The lowering of ground is mainly caused by excessive exploitation of underground water, which has led to damage of buildings, bridges, underground pipelines and dysfunction of urban drainage system, according to the report.

The State Council has approved a plan of preventing land subsidence from 2011 to 2020, which was jointly created by several ministries and commissions including Ministry of land and Resources.

Guan Fengjun, director of geological environment department of Ministry of Land and Resources, said the main method to control land subsidence is to prevent underground water from dropping.

The report said some cities have taken strict measures to limit collecting underground water.

In Xi'an, capital of Northwest China's Shaanxi province, more than 1,000 wells have been sealed after 150 square kilometers of land dropped more than 200 millimeters since 1959.

Shanghai, located at the Yangtze River Delta is recharging underground water through 121 wells with more than 60,000 tons every day.