Differing duties

City governments are responsible for chengguan, which means their duties vary in different places.

For instance, in Chengdu, capital of Sichuan province, officers can fine people for noise pollution, while in Guangzhou, capital of Guangdong province, the environmental protection bureau handles this issue.

There is no central authority in charge of chengguan, and no specific law or regulation about how they can enforce bylaws, said Luo Yameng, director of the China City International Association, an NGO dedicated to researching urban management.

"Even the chengguan uniforms are different from place to place," he said.

To avoid conflict, officers in some cities have introduced innovative measures, such as in Wuhan, capital of Hebei province, where they tackle street vendors by surrounding them and staring at them until they move on, Changjiang Times reported.

However, Luo has urged the National People's Congress, the top legislative body, to introduce rules to keep urban management authorities in check.

In some large and coastal cities, chengguan are well trained, yet those in smaller remote cities rarely receive professional training and are "prone to be violent", he said.

Controversial case

In May 2011, a court in Shenyang, capital of Liaoning province, sentenced Xia Junfeng to death after he stabbed to death two chengguan during an argument over his food stall.

The Supreme People's Court is reviewing his case, but he remains on death row.

Many netizens and media commentators have called for Xia to be spared, claiming the officers were guilty of provocation.

Such debate on who is to blame for conflicts is common, according to Song Zhigang, a chengguan in Beijing's Haidian district. He has written a book about his experiences in the job, and said the public often misunderstands the purpose of the authority.

"Our goal in not to eradicate unlicensed vendors, but to prevent them blocking traffic or affecting the life of nearby residents," he said.

Many people complain to chengguan that unlicensed vendors destroy the environment, such as by littering, using polluting barbecues, and occupying parking spaces, Song said. On the other hand, he said, other people accuse chengguan of affecting the livelihoods of vendors.

"All are taxpayers, so who should we listen to?" he said.