Shanghai traffic police have asked driver's training institutes to limit the number of applicants who are not locally registered, leading to a price increase that authorities have promised to clamp down on.

A Shanghai traffic police officer said Wednesday that authorities has forbidden all driver's training institutes from raising fees for applicants who do not have a Shanghai "hukou," or household registration. The hukou identifies its holder as a permanent resident of a given Chinese city, entitling the holder to favorable policies in the city in which they are registered.

Traffic police have capped the number of hukou-less applicants to 23,000 per month due to"finite training resources" and a "decline in training quality," according to a document obtained from Shanghai's traffic police.

Applicants without a Shanghai hukou said the quota has compelled them to pay 10 to 20 percent more in fees and stay on a waiting list for over half a year.

Some applicants believed the order was made to ease traffic congestion in Shanghai, as Chinese regulations require people to enroll in driver's training institutes in order to pass driver's license tests.

The quota has been fiercely attacked by non-hukou applicants, who said they work and pay taxes just like those who have a Shanghai hukou.

From January to September, about 55 percent of the city's driver's license applicants lacked a local hukou, according to police statistics.

The current quota is too tight, causing price spikes and enrollment delays, said a manager of a major driver's training institute in Shanghai.

Shanghai traffic police have no authority to use the hukou as a standard for admission to driver's training institutes, said Zou Rong, a law professor at the East China University of Political Science and Law.