Some eight million people live in Beijing without a permanent residence permit, a huge army of "Beipiao" -- outsiders who work and live in Beijing with great ambition but without permanent homes or a decent quality of life. Many Beipiao live in basements, unable to afford a room above ground. Liu is one of them.

The flute major has never had a permanent job since graduating in 2012. He earns his living tutoring kids. He never has a free weekend as he must work whenever the children are out of school. His schedule is full during the summer holiday and he has finally earned enough money to move above ground, but the slack season is approaching and he is worried. Liu has no plans to leave the city. "I will stay here and fight for a better life," he said.

In Foshan, Guangdong province, Huang Ziyun works for an electrical appliance manufacturer. She graduated from Beijing Foreign Studies University in June and her family begged her to go back home.

She misses Beijing where she could see the world's greatest artists perform and meet many people of different races and cultures.

Huang plans to return to Beijing to continue her studies; a good excuse for her to leave home again. "I will certainly head back north when the time is ripe," she said.