A senior official is calling on residents of this southern city to "stop buying cars".

"Problems arising from the city's traffic are mounting. I hope residents take this into consideration when planning to buy cars," Xu Zongheng, mayor of Shenzhen, said.

City Mayor of Shenzhen, Xu Zongheng (file photo)

He said people in Shenzhen were buying cars "too quickly".

"The annual growth rate of cars is 18.6 percent which outstrips road construction, and about 70 percent of the city's air pollution is caused by exhaust fumes," Xu said.

A Shenzhen traffic police department report shows the total number of automobiles has exceeded one million. In the first half of this year, about 90,000 new cars were registered in Shenzhen.

"The total number of newly purchased and registered cars may exceed 200,000 by the end of the year," the report said.

Shenzhen vice-mayor, Zhang Siping, said: "The huge traffic flow is presenting difficult challenges to the city's planning, traffic and environment protection departments."

A Shenzhen traffic police officer said: "Shenzhen has 2,174 km of roads. If the cars are lined up they will circle the city twice."

To alleviate the problem, Shenzhen has expedited the expansion of its public transport network, and the building of highways.

"In addition to increasing bus routes we will finish the construction of No 1, 2, 3, 4, 5 subway lines as well as the extension of No 2 and 3 subway lines before June 30, 2011. The railway will be stretched to 155 km," Zhang said.

"We will also invest about 50 billion yuan (US$6.4 billion) in establishing a high-speed road network. We aim to build 130 km of expressways and 337 km of roads by 2030."

Yang Sizhong, a visiting professor with the Shenzhen University, said: "An extensive, fast and convenient public transport network would dampen the crave for private cars."

(China Daily July 6, 2007)