The local government in Guangzhou decided to put a cap on car sales starting Sunday, making Guangzhou the fourth Chinese city to use car quotas to tackle traffic gridlock and air pollution. Since July 1, no more than 10,000 new cars can be registered every month in the city.

The sudden announcement of the new limit late Saturday instantly sparked long queues in auto dealerships across the city. Online, complaints and anger from local residents, whose plans for car purchases have been disrupted, are widespread.

According to the international standard of 20 cars per 100 families, the Chinese have already become an auto society. As cars become the new must-have for Chinese families, the country is tasting the full bitterness of being an auto society. Heavy traffic and choking smog have become common scenes in Chinese cities.

But compared to car density in rich countries, China is far from a true auto country. Statistics show that the US has the highest vehicle-to-person ratio in the world, about 1:1.3, while the ratio in China is about 1:17.2 among the country's 1.3 billion people.

It is beyond imagination how much petrol will be consumed if China reaches the same level of car ownership and Chinese become as enthusiastic about gas-guzzling vehicles as Americans are. 

Besides, the problem in China also seems to be much more complicated. Behind the traffic jams in Chinese cities are chronic problems of energy shortage, transportation systems that need improving, and urban management levels that often seem to lag behind actual needs.

Limiting the number of cars on the road is a painful but unavoidable choice for many big Chinese cities. But how to make it happen will make a difference among consumers.

Many local residents whine about the absence of having hearings before a policy with such a wide affect is suddenly implemented. Local governments should consider this request.

Shanghai, another city burdened by heavy traffic, attempts to restrict car numbers by putting new license plates up for auction. Some think the market-based approach is better than simply limiting the number of new cars, while others hold it favors the wealthy.

The massive population has long been the root of national problems here. When Chinese tourists go on milk-powder shopping sprees while traveling overseas after the domestic milk scandal in 2008, many retailers abroad imposed a cap on diary products each Chinese tourist can buy.

When resources appear so scarce before a huge population, the government has to first curb the explosive demand. Limiting car sales will no doubt hurt the local economy. Between traffic, environment, economy and people's desire to drive, it is difficult to find a cure-all solution.