FACTBOX: Beijing's battle for blue skies

(Reuters) - China's capital has spent 140 billion yuan ($20.34 billion) to combat chronic pollution and create a clean, green Beijing ahead of the August 8-24 Olympics.

Here are some of the green moves the city of 15 million people and 3 million cars has announced:

SWITCHING FROM COAL TO GAS

-- Already the top consumer of natural gas among Chinese cities, Beijing's usage grew to an estimated 4.7 billion cubic meters in 2007 as it tried to cut back on the 26 million tonnes of polluting coal it consumes a year.

-- By the end of 2006, 15,200 coal-fired boilers, of 16,300 in the city, were converted to natural gas or other clean fuels.

CLOSING OR RELOCATING HEAVY POLLUTERS

-- Authorities in Tangshan, an industrial city north of Beijing, ordered 267 firms to shut down operations by July 8 to improve air quality ahead of the Olympics.

-- Tianjin, a port city just east of Beijing, ordered 40 factories to shut from July 25 to September 20.

-- Steel-maker Capital Steel, long Beijing's worst polluter, has relocated most operations out to coastal Hebei Province, with the rest to follow by 2010. In July 2006, production ceased at another major polluter, the Beijing Coking and Chemical Factory.

TARGETING PRIVATE CRAS

-- Beijing took 300,000 high-emission cars off its roads on July 1, banning them until Sept 20. In January it tightened emissions standards introduced in 2005 to cut pollution from private cars exhausts, which pump out 80 percent of the carbon monoxide in Beijing's skies.

-- From July 20 private cars will be banned on alternate days according to odd/even number plates -- a move officials hope will take 45 percent of the city's 3.29 million cars off the roads.

GREENING THE TRANSPORT SYSTEM

-- A new north-south subway line opened in October 2007, and another east-west line is scheduled to open before the Games. Subway ticket prices are 2 yuan (about 29 cents) to woo commuters off the roads, while Games spectators with tickets will travel free on public transport.

-- Beijing retired or refitted 47,000 old taxis, and 7,000 old diesel buses, out of a fleet of 60,000 taxis and 19,000 buses, and unleashed a fleet of 3,795 natural gas-powered buses.

COVERING DUST FROM CONSTRUCTION