In an effort to reduce smog and as a run-up to the 2008 Beijing Summer Olympics, China scheduled a no car day in more than 100 cities. Vehicles were prohibited in Beijing's main streets, while car owners were encouraged to leave their automobiles at home.

The event was held amid high hopes and to avoid the threat of having some of next year's Olympic events postponed.

The campaign sought to encourage at least half of China's urban residents to take public transportation. State officials and employees in certain cities were asked not to drive their vehicles, while some cities banned government-owned cars from plying the cities' streets.

"The move is an attempt to raise residents' awareness on energy saving and environmental protection because the country's cities are plagued by traffic congestion and pollution," China Daily had explained.

But millions of private vehicles drove through the streets, ignoring the National No Car Day held on Saturday.

There is a campaign among environmentalists in China for a revamp in the country's transportation system to go beyond No Car Days, which are far and few in between. The proposals include adding more bicycle lanes, decreasing the cost of public transportation and placing more stringent requirements to own a private car.

Beyond health concerns for city residents, the other driving factor behind efforts to reduce the volume of private vehicles and smog is to ensure the success of next year's summer games to be held in China's capital.

The head of the International Olympic Committee had earlier threatened to postpone some events such as cycling and marathon is pollution level remains high by next summer.