For the second group, who pursue better jobs and higher incomes, the attraction of Beijing lies mainly in the greater opportunities it offers. The job opportunities they seek are primarily in industries such as construction and the service sector. As long as the city and its population continue to grow in size, people will continue to be attracted to the capital.

The accumulation of people creates jobs, which in turn attracts more people to accumulate.

Clearly, Beijing's population growth will not ease dramatically in the short term. For Chaoyang district, it is the job opportunities, mainly in the service sector, that attract large numbers of people to the area. A growing demand for housing is a result, not a cause, of population pressure in Chaoyang. So controlling the supply of housing will not curb the growth in Chaoyang's population.

In the face of the already very high cost of housing, those who come to the city in search of better paying low-end jobs have to choose between group renting or underground renting to find a place to sleep at night. If the authorities of Chaoyang district launch a crackdown on such renting, the workers will only move out of the district into some farther away suburban districts, such as Tongzhou; or even farther away into neighboring Hebei province. There are already reports of the about 300,000 people who work in Beijing and reside in Yanjiao, a small town in Hebei province.

In this way, the move proposed by Chaoyang officials might not directly serve people's daily needs. Traffic jams, especially during the rush hours, will happen more frequently in and near Beijing, while buses and subways will be more crowded. There will be other effects including a higher consumption of resources, plus lower efficiency and higher costs due to long-distance travels.

While it might be possible to curb the population growth in the long run by controlling housing - when the costs of living in or near Beijing are high enough to counteract the higher salaries and better job opportunities here, people will stop rushing in to dig gold. But that will be the day when Beijing's housing prices and other costs skyrocket and far exceed that of ordinary income levels, that would make the metropolis even more of a heaven of the super rich. The city would lose both its competitiveness and economic vitality. In the long run, the whole region of North China will decline, too, to which Beijing is the lead and center. Is that what Chaoyang officials mean by "controlling the population"?

The author is a researcher at the China Center for Urban Development.