The black market in Beijing household registrations is likely to continue despite a crackdown by police who detained a gang involved in the trade, say experts.

The gang allegedly pocketed more than 3 million yuan ($486,000) by exploiting hukou, the household registration system. They helped 80 university graduates to obtain documents even though they were not eligible, say police.

The Beijing procuratorate approved the arrest of 13 people on suspicion of selling official documents and abusing power.