"The best time to be out is lunch time, when the chengguan are on break," said Meng Xiandong, 54, a vendor of dried sweet potatoes, as he nervously scanned the crowds.

Hardly a week goes by without a new controversy involving the municipal officers, a rung below the police, beating an unlicensed hawker or smashing a street vendor's stand.

Chengguan, an urban control force charged with keeping the peace, ridding China's cities of illegal street hawkers and unlicensed taxi cabs, and checking permits.