Beijing, China's capital, is sinking at an alarming rate.

According to a study published in the journal Remote Sensing, the pumping of groundwater is causing the Chinese capital - specifically the Chaoyang district - to sink as fast as four inches every year.

Apart from Chaoyang district, where many hotels and office buildings stand, other central districts are also affected, including Changping, Shunyi and Tongzhou districts.

"The maximum subsidence is seen in the eastern part of Beijing with a rate greater than 100 mm/year," the researchers wrote.

According to a report in CNN, Beijing, which is home to over 20 million people, is ranked the fifth most water-stressed city in the world, consuming about 3.5 billion liters per year - two-thirds of which comes from the groundwater.

As the water is extracted, the surrounding soil dries up and compacts. The rapid urban growth has caused an increase in the demand for water, and the continuous construction of massive buildings, roads and other infrastructures is adding up a large amount of weight on the ground.

The researchers, which is composed of an international team led by Beijing-based scientists, used satellite images and GPS collected between 2003 and 2010 in observing the phenomenon. Land elevation changes are being monitored using InSAR radar technology.

The rapid sinking could affect buildings and public works projects, including the city's vast rail network.

According to the researchers, the sinking could be temporarily eased by proper enforcement of groundwater pumping regulations. The same had been done by Shanghai, which had also been sinking four inches every year in the 1950's and 60's but has now fallen less than half of an inch after following rules on groundwater use.

Five years ago, drought in southern China has caused billions of dollars worth of agricultural losses and water shortage to millions of people. Massive infrastructure projects had been undertaken to divert water to affected regions, particularly in northern China.

Earlier this year, a NASA airborne radar also revealed that New Orleans in the U.S. was also sinking at "highly variable rates," and researchers found that groundwater withdrawal was among the top reasons behind the sinking.