The collapse happened near the northern part of Second Ring Road.

　　According to Beijing's urban planning commission, the owner had dug a basement about 18 meters deep in a courtyard, without first obtaining a construction permit.

　　The cave-in left a 10-meter-deep hole on the ground and caused the collapse of 4 neighboring houses. 15 people have been forced to evacuate their homes.

　　An apartment building nearby is being monitored after its foundation was shaken.

　　Media reports say about 4,000 tons of cement have been used to fill the hole.

　　Wang Wei is an official from the city's construction watchdog.

　　"From the information we have so far, the owner started the operation without obtaining a permit for underground construction. This is a crime of illegal construction. The nature of the accident goes beyond that. It caused the road to sink and the surrounding houses to collapse. It should be regarded as an incident caused by illegal construction."

　　The accident soon grabbed public attention after media reports revealed that the courtyard belongs to Li Baojun, a lawmaker from Xuzhou city in Jiangsu Province.

　　Li has not commented on the accident, which happened over the weekend.

　　违法建设导致道路塌方

　　Officials from Xuzhou say they will deal with the case after receiving official notification from Beijing.

　　People living near Li's residence say they had reported the construction to the relevant authorities. Officials say they had ordered Li to stop the illegal construction last July but it continued in secret.

　　Bian Lanchun, a professor from the School of Architecture of Tsinghua University.

　　"There are many motives for illegal construction. Some people may commit this crime because of a lack of living space. But of course, there are some people who commit this act who are driven by other interests. I think to solve this problem, on one hand we should improve the legal system, and on the other hand advocate public involvement and build a more extensive supervision system."

　　Reports on illegal construction projects have been increasing in recent years.

　　In 2013, a massive rooftop villa in Beijing shocked the country. It had an area of 800 square meters and artificial gardens and rocks. It has since been demolished.

　　For CRI, I'm Luo Wen.