The figure breaks down into 12.04 million holders of Beijing "hukou", or household registration certificates, and 5.1 million floating population, sources with the Ministry of Public Security said at Monday's workshop on the country's management of migrants.

Beijing municipal government announced last year it would limit its population to 18 million by 2020.

Overpopulation is putting considerable pressure on the city's natural resources and environment. And experts have warned the current population, 17 million calculated at the end of June, is already 3 million more than Beijing's resources can feed.

Given this year's baby boom, triggered by the superstitious belief that babies born in the Chinese year of the pig are lucky, analysts say there is little hope for an immediate slowdown in Beijing's population growth, even with the post-Beijing Olympics lull and soaring housing prices that have driven some Beijingers to boom towns in the neighboring Hebei Province and Tianjin Municipality.

Migrants, especially surplus rural laborers who have taken up non-agricultural jobs in the city, have forcefully contributed to the population explosion in recent years.

About 200 million migrants are working in cities across China.

Last year, Ministry of Public Security proposed police authorities in the migrants' home province should send "resident police officers" to cities to help maintain public security at major migrant communities, many of which are slums that are prone to violence, robberies, drugs and gambling.

Resident policemen are currently at work in three cities: Dongguan, a manufacturing center in Guangdong Province, Binzhou of the central Hunan Province and Guigang of the southern Guangxi Zhuang Autonomous Region.

The ministry has also demanded all cities to complete a management information system of migrants' data by the end of 2009.

（英语点津 Linda 编辑）