TIANJIN -- The city of Tianjin is considering tightening groundwater management to cope with geological problems and water shortages caused by long-term over exploitation.

The North China city has been threatened by a severe water shortage, with the volume of water flowing into the sea reduced from 14 billion cubic meters in the 1960s to one billion in 2017. The per capita water resources in the city are only one-twentieth of the national average, according to Shi Jin, deputy head of Tianjin Environmental Protection Bureau.

Accordingly, groundwater has become a major source of water supply in Tianjin, but overuse has led to geological problems such as funnel-shaped depressions in water tables, Shi told a recent meeting of the Standing Committee of the Tianjin Municipal People's Congress.

Shi said the city's over-abstraction area reached 9,440 square kilometers as of 2017, and 6,624 square kilometers of funnel-shaped depressions have been identified.

To protect groundwater resources, Tianjin will delimit specific areas that ban or limit water exploitation, and cope with land subsidence problems in the city.

Shi said the city plans to ban more than 1,300 companies from using groundwater resources and cap the annual extraction of deep groundwater resource to 89 million cubic meters by 2020.

Tianjin has received more than 1.8 billion cubic meters of water via the south-to-north water diversion project since December 2014, which also provides support in reducing groundwater consumption.