Excessive exploitation of groundwater in downtown Beijing and the reduced volume for storage have aggravated the instability of the water ecosystem, according to a regional development report released on Thursday.

"Beijing, Tianjin and Hebei need to coordinate to protect the source of drinking water," said the 2015 Annual Report on Beijing-Tianjin-Hebei Metropolitan Region Development.

The report points out that due to geographical location and climate, the cities in the region suffer from a natural shortage of water.

It also says that ground-water has been overextracted, and that the underground infrastructure in Beijing, such as the subway system and pipelines, has decreased the volume of underground storage area for water.

Also pollution has become a serious problem, with hundreds of waste yards and informal landfills in the Beijing area. After rain, garbage in the dumps may seep into the groundwater and reduce its quality.

The report highlighted analysis of groundwater around a dump in the Fengtai district of Beijing, where the amount of ammonia and nitrogen was found to be 29 times higher than normal.

Statistics in the report show that from 2001 to 2013, the average amount of water available to Beijing was 2.48 billion cubic meters, nearly 1.06 billion cubic meters less than its average water consumption.

At the end of last year, the South-to-North Water Diversion Project began supplying water to Beijing, with the capacity of channeling 1.05 billion cubic meters of water annually from South China.

In Tianjin, a megacity neighboring the capital, the amount of available water in normal years is about 1.38 billion cubic meters, while the total water consumption is around 2.21 billion cubic meters. The shortfall of 830 million cubic meters was made up through overexploitation of groundwater and water diversion from neighboring provinces.