Beijing municipal people's congress revealed this week that the capital now has 19.72 million inhabitants.

Previous estimates had predicted that the city's population would swell to that level a decade later than it has.

Beijing women doing outdoor exercises. [File photo]

According to the guidelines regarding Beijing's development between 2004 and 2020 set by the State Council, the number of permanent residents living in capital should have been capped below 18 million until the end of 2020.

However, a recently released report from the population investigation and research team within the people's congress shows that by the end of 2009, approximately 12.46 million people in the capital held a Beijing hukou. An additional 7.26 million inhabitants were migrant workers who had been living in the city for more than half a year and who are therefore also classified as permanent residents.

After analyzing the change in population between 2006 and 2009, the team found that Beijing's population had undergone rapid growth during the first four years of the 11th Five-Year Development Plan, mainly as a result of an explosion in the floating population.

Natural birth contributed 482,000 extra people during the past four years while the jump in the floating population accounted for 1.52 million additional inhabitants.

The report points out that now the total size of the floating population in the capital could have exceeded 10 million people, if members of the army deployed in Beijing, unregistered migrant workers and people on short visits are also added to the mix.

The massive growth in Beijing's population, which is mainly comprised of young adults, plays an important role in the booming development of the city. Unfortunately, say critics, it unavoidably brings more pressure on the city's natural resources.

Wang Jian, a water specialist with Green SOS, an NGO based in Beijing, told METRO that the current water reserves in Beijing can only support about half of its residents, and not the nearly 20 million people who now live in the city.

The population explosion not only burdens the environment but also the whole infrastructure, public service system and the management of society, say experts.