(CNN) The population of Beijing fell for the first time in two decades, state media reported Wednesday, amid ongoing efforts by the city's government to drive out migrant workers.

Beijing's population dropped by 0.1% in 2017, according to government figures, with 22,000 fewer permanent residents than the previous year.

In total, China's capital has a population of 21.7 million people, more than London and New York combined.

It was the first time both city's populations fell in the same year in four decades, state media reported.