Beijing's population looks set to swell to 21.4 million by 2020, far exceeding the threshold of 18 million set by local government, a report said over the weekend.

The population surge will put more strain on water, land and food resources for the city and its surrounding areas, stated the Strategic Report on the Population of Beijing, Tianjin and Hebei on Saturday.

The report was released at the Beijing Population and Development Forum, organized by the Beijing Population and Family Planning Commission.

The rapid population growth in the capital is mainly fueled by the constant influx of migrants, Zhai Zhenwu, a professor with the Population and Development Institute of the Renmin University of China, said.

"Although Beijing saw zero growth in the natural birth rate for the past five years, its population kept expanding as a result of the massive inflow of migrants," Zhai said.

There are more than 17.4 million people in Beijing now, of which about 12 million are permanent residents and the rest migrants, figures released last Monday by the committee's deputy director, Li Yunli, showed.

About 130,000 new babies were born in Beijing from January to October this year, including 40,500 babies from migrant families, statistics showed.

In the next five to 10 years, the capital will see continuous population growth, Li said.

The 1980s saw a baby boom in Beijing and women born in that period are now between 20 to 29 years old - a fertile period for them.

At the same time, couples who are both from one-child families can have two children, which will also help to increase the city's numbers, she said.

Experts have suggested that the population of Beijing should be kept under 17 million, while the total population in Beijing and the surrounding Tianjin Municipality and Hebei Province, below 110 million.

Researchers also called for closer cooperation in economic development in Beijing, Tianjin and Hebei to narrow gaps in development among the three regions.

(China Daily December 10, 2007)