A migrant worker plays guitar at Migrant Workers Home in Picun village, Beijing's Chaoyang district. Photo: VCG

Beijing's official permanent migrant resident population fell for a third year in 2018, according to the Beijing Population Blue Book published over the weekenday. 

The paper, based on data released by the Beijing Municipal Bureau of Statistics, Civil Affairs Bureau and other authorities, indicated that the size of the permanent migrant population in the capital has been shrinking for three consecutive years since 2015. 

The migrant population was 8.23 million in 2015, declining 1.84 percent to 8.08 million in 2016, 1.63 percent to 7.94 million in 2017 and 3.74 percent to 7.74 million in 2018, according to the paper. 

"It's normal to see a decline in cities' population," Liu Zhijun, a professor of sociology at Zhejiang University told the Global Times on Sunday.

"After rapid expansion, there will always be a point for a city's population to begin decreasing and now is about the time."

The rapid development of second-tier cities such as Hangzhou and Nanjing has attracted workers who have gradually left first-tier cities like Beijing, said an expert who requested anonymity. 

Beijing government implemented the plan to manage the population in response to rising numbers of migrants which experts said brought about some problems like pollution and safety problems . 

Liu noted a deadly fire in Beijing's Daxing district at the end of 2017 as hastening the pace of government action against migrant workers. 

The Beijing government's approach has made notable progress in coordinating population, resources and environment, Chinese experts told the Global Times on Sunday.  

Due to the reduced migrant population, Beijing's resident population also experienced consecutive declines in 2017 and 2018. The total population in 2018 was around 21.5 million.

The size of Beijing's permanent population is planned to be controlled within 23 million by 2020, according to a State Council plan issued in September 2017, and that number is intended to remain stable afterwards.