How did you come to photograph the people living in Bejing’s basements?

In 2007, I moved to China as a foreign correspondent for the Straits Times. I came across the cellars by chance. Someone told me he was running a basement with small rooms built into it. I was immediately fascinated: There is an alien universe under our feet. From 2011 to about 2015, I took portraits of these people.

Who are the people in the photos and how did you find them?

They are migrant workers from poorer areas of China. They are the backbone of the service industry in Beijing: the people who run stores, waitresses, hairdressers. I often found them when I was sitting in a restaurant or having my hair cut. I would ask, “Where do you live?” Usually the answer was, “I live in the basement.” I then invited myself over to photograph them.

Why did you take the photos?

My goal was to make these people, who are known as “shuzu” (“rat people”) visible. I wanted to show that they are no different than the people who live above ground. When you meet them on the street, you can't tell where they live.

What kind of basements form their homes?

On the one hand, there are bunkers built by the Ministry of Defense. They are found under public housing, commercial buildings and private condominiums. In the 1950s, every house in Beijing had to have such a basement because Mao was afraid of a nuclear attack by the Soviet Union.

Why did people start to move to these underground places?

In the 1990s, Beijing experienced a boom and many people moved into the city. There was a shortage of apartments, so the city government allowed the rooms to be used as living space. It rented them out to private individuals, who often sublet them to migrants.

How can we imagine these cellars?

Some of them are up to four stories deep, i.e. up to ten meters underground. The corridors are long and narrow, like in a labyrinth. In winter, it's warm down there because heating pipes run through the rooms. But it is very humid. In some cellars there are 150 or 200 rooms. The smallest room I ever saw I couldn't photograph because the man who lived there was so ashamed. It was  under a staircase, with only a bed and a small desk in it.

Did living in the basement harm people's health?

Many people I talked to were afraid of living in the big city, so they hid themselves in this underground world. But they felt very isolated there. Also, the lack of sunlight was definitely not good for their psyche.

Why do the people you photographed no longer live there today?

It is now forbidden to live in the cellars. In 2015, police officers came to close them down. Some of these people told me at the time: I should see how they fought for their homes and for compensation.

To this day, there are reports that the Chinese authorities are closing down basements of this kind. Why?

For one thing, because of safety concerns. During a severe storm in 2012, two or three people wereelectrocuted because their cellars were flooded. But I think there were also efforts by the government to reduce the number of migrant workers in Beijing. That was also achieved by taking away their living space – that makes them leave.