149 major cities see populations shrink

Appeal of regional hubs

The latest census data showed about 376 million, or one in every four people in the Chinese mainland, were classified as migrants living outside their hometowns in prefecture-level cities or regions, up 70 percent from a decade ago.

Ding Changfa, an associate professor of economics at Xiamen University in Fujian province, said the capital cities of the central provinces had absorbed large numbers of migrants due to their roles as regional economic hubs.

For example, Changsha, capital of Hunan, had gained more than 3 million people to now have a population of more than 10 million. Xi'an, Shaanxi's provincial capital, gained almost 3.9 million people.

Jiang Quanbao, a professor at Xi'an Jiaotong University, said provincial capitals appeal to migrants because they offer more opportunities and have introduced policies designed to attract talent.

"With transportation within the provinces getting better in recent years, the appeal will become stronger," he said.

The flip side of the population outflows has seen another 184 cities expand and boom. Some have even moved to limit new arrivals because of concerns about so-called big city problems such as congestion and water shortages.

The eastern province of Zhejiang, a stronghold of private businesses and the seat of e-commerce giant Alibaba, reported population increases in all its cities.

Population growth has also been recorded in places including the Tibet autonomous region and Guizhou province in Southwest China. However, experts say that's mainly because of higher fertility rates.

Not long ago, the two regions were home to some of China's most entrenched poverty. They managed to end widespread impoverishment through mass relocation programs and infrastructure development projects.

Jiang said the migration pattern－from inland to coastal regions, from smaller cities to provincial capitals and from rural to urban regions－requires policymakers to plan in advance to avoid "useless "investment. "We used to invest greatly in rural education, but some of the investment later turned out to be a waste of money as many such schools were idled because there are no students," he said.

He said that retaining all the people in the countryside is not the only path to vitalize rural areas, and that some villages could, instead, serve as industrial bases.

Yang Yifan, deputy head of the National Interdisciplinary Institute on Aging affiliated with Southwest Jiaotong University in Chengdu, Sichuan province, said people congregating in bigger cities helps improve efficiency and reduce the cost of public services, but the marginal returns diminish as cities grow too large.

"Local governments need to take active, and wiser, measures to perfect the city's layout and retain talent," he said.