GUANGZHOU, China — It is as startling as if Detroit or Los Angeles restricted car ownership.

The municipal government of Guangzhou, a sprawling metropolis that is one of China’s biggest auto manufacturing centers, introduced license plate auctions and lotteries last week that will roughly halve the number of new cars on the streets.

The crackdown by China’s third-largest city is the most restrictive in a series of moves by big Chinese cities that are putting quality-of-life issues ahead of short-term economic growth, something the central government has struggled to do on a national scale.

The measures have the potential to help clean up China’s notoriously dirty air and water, reduce long-term health care costs and improve the long-term quality of Chinese growth. But they are also imposing short-term costs, economists say, at a time when policy makers in Beijing and around the world are already concerned about a sharp economic slowdown in China.

“Of course from the government’s point of view, we give up some growth, but to achieve better health for all citizens, it is definitely worth it,” said Chen Haotian, the vice director of Guangzhou’s top planning agency.