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By Ben Blanchard

BEIJING, July 20 (Reuters) - Beijingers breathed easier on Sunday as traffic restrictions and factory closures came into effect in a last ditch attempt to turn the often smoggy Chinese capital into a pollution-free venue for next month's Olympics.

On a sunny but still slightly hazy day, the flow of cars was lighter than usual for a Sunday on the city's wide roads, as vehicles with odd licence plates were banned from the streets for the day. Tomorrow even-numbered cars must stay in the garage.

"Its great -- today there are far fewer cars on the road and the air quality is so nice. This is good for the children," said 20-year old Wang Yanna, out for a weekend stroll with her toddler nephew near a busy intersection.

The city's chronic pollution has been one of the biggest headaches for Games organisers, who are banking on traffic restrictions and last-minute industrial cut-backs to bring blue skies and easy breathing for athletes during the Games.

Under the new rules cars are banned on alternate days depending on their licence plate number and most official cars have been impounded. Only taxis and Olympic vehicles are exempt.

The government hopes to take around 60 percent of the city's 3.3 million cars off the roads, the official Xinhua agency reported, and reduce emissions by two-thirds over the two months until the end of the Paralympic Games in mid-September.

Most building work has also halted and almost all earth and cement works have been closed, along with a string of factories -- including many in other provinces. Some are more than 100 kilometres away but still contribute to the pollution which earned the nickname "Grayjing" for the city.

Tianjin, a port city just east of Beijing and host to Olympic soccer qualifiers, has ordered 40 factories to close. Tangshan, a heavy industrial base northeast of Beijing will shut nearly 300 factories this month to improve air quality for the Games.

TAXIS HAPPY, DRIVERS MAD

With more than 1,000 new cars hitting the street every day, Beijing is becoming one of the world's most congested cities. So taxi drivers, used to losing money as they idle in the city's epic traffic jams, were thrilled about the new regime.

"Its going to be great for business. Look the traffic is already so much better, its much easier to drive today," said a smiling Han Jianguo from behind the wheel of his cab.

Ordinary Beijingers were not all so enthusiastic, though most were willing to make sacrifices to ensure the Games run smoothly.

"The rules will certainly help (with congestion). But it will bring some real difficulties in transportation for ordinary people," said driver Liu Shuo, before his wife hushed him for criticising Olympic preparations.

The city has warned that people who violate the rules will be caught by a high-tech surveillance network of over 10,000 "smart" devices, including cameras, ultrasonic and microwave scanners.

An extra 4 million people are expected to cram onto the city's already-crowded public transport network, although new Olympic metro lines and an airport express that opened at the weekend will provide some relief.

Some athletes still have lingering doubts about air quality, but Beijing says it is making an all-out effort. It has spent 120 billion yuan ($17.58 billion) to clean up the environment, and already ordered 300,000 high-emission cars off its roads.

It is keen to ensure a safe and attractive city as well as a pollution-free one, so extra security measures also started on Saturday and Beijingers took to the streets to help lost tourists and try to restrain their more unruly neighbours.

Hundreds of "social volunteers" policing a ban on unwelcome behaviour like littering and spitting lined Beijing's main Chang'an avenue in matching red caps and red-trimmed polo shirts.

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For a factbox on factory closures, please doubleclick on [ID:nPEK253453]

For a factbox on other Olympic preparations, please doubleclick on [ID:nPEK251677]

* * * * * ($1=6.826 Yuan) (Additional reporting by Ian Ransom and Tyra Dempster; Editing by Emma Graham-Harrison and Alex Richardson) (For more stories visit our multimedia website "Road to Beijing" at http://www.reuters.com/news/sports/2008olympics; and see our blog at http://blogs.reuters.com/china)

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