Percent of a major city's QQ users who moved away. [Photo by Wang Xiaoying/China Daily]

Lack of opportunities

Zhang Jialu, 27, says she had a huge range of free-time opportunities on offer to her in Beijing－but which she would eventually abandon.

"Those who live in the metropolises have a rich variety of cultural events and activities available to them. It's easy to find something that appeals to you no matter what your interest is."

Zhang worked in Beijing for less than four years before quitting her job in May 2014 to return to her hometown of Zhoushan, Zhejiang province, initially to take a rest for several months.

Her parents regarded Beijing, more than 1,200 kilometers from Zhoushan, as being too distant and housing prices as unaffordable, she says, and wanted her to work in a city nearer home. So she took up a job in marketing in an Internet company in Hangzhou, the capital of Zhejiang, about 200 kilometres away.

However, Zhang says the decision to relocate has left her with a feeling of loss, and she has failed to find her feet in Hangzhou.

"At work, things are slower, and the same applies to the pace of life. I have more spare time but I'm not passionate about life the way I used to be. In my mind I don't feel as young or as energetic as I did before, either.

"Beijing suits me better because the competitiveness that there is in the city makes me work harder. Another thing is that those you work with are more likely to let you know what they think and encourage you if you have a creative idea."

Zhang says the inclusiveness of people in Beijing also suits her because she is sociable, but people in Hangzhou are less inclusive, which has made it difficult for her to integrate.

In Beijing she rented an apartment with people who were strangers at the start but with whom she formed good friendships, but in Hangzhou she lives alone in her own house and misses the company and other friends.

Six months ago she seriously considered returning to Beijing to work, she says, and the only thing that has kept her from taking that step is the pollution.

"I didn't leave because of that, but at present it is what is keeping me from going back."