From May 1st, it is illegal for a group of people to collectively rent one room in China. But many on low incomes in big cities can only afford to rent in this way.

In a residential building in Beijing, this group is renting this property despite the announcement making it illegal.

Most who rent in this way aren't aware that it's illegal. However, even if they did know, they have no choice if they want to stay in the city.

In Beijing, average rent was above 3000 yuan per month last year - up 23 percent from 2009. While it only takes several hundreds yuan for group renting.

The math is attractive. Renting a room or small property with a group costs the individual tenant less, making it very appealing to those on low incomes.

Professor Lian Si, UIBE, said, "In Beijing, there are more than 150 thousand university graduates who group rent. They can't afford to rent an individual apartment as their average salary is about 2000 yuan per month."

Those on low incomes can only afford to live in big cities by renting properties in groups. The new prohibition may force many to return home, leaving an employment vacuum the government will need to fill.