Despite China's enormous efforts to improve Beijing's air quality for the Olympic Games, pollution caused by nearby factories and the city's 3.56 million cars remain a major problem, the official Xinhua News Agency reported.

Xinhua said Beijing registered 65,970 new vehicles in the first 45 days of the year. Drivers must register their vehicles before they can drive in the capital.

Driving restrictions imposed during the Olympic Games that cut car use in half allowed Beijing's 17 million residents to enjoy clear blue summer skies as the city recorded its lowest August pollution levels in 10 years.

Beijing has now imposed trial restrictions, which last until April 10, that take every vehicle off the road once a week. The law does not apply to emergency vehicles, taxies and buses.

The number of new driver licenses issued since the beginning of this year totaled 58,590, bringing the city's driving population to 5.2 million, according to the Beijing Traffic Management Bureau cited by Xinhua. More than 65,000 vehicles have been registered in the capital. -- AP