By Chris Buckley
BEIJING (Reuters) - Olympic host city Beijing was shroudedin haze on Monday 11 days before the Games begin, raisinganxieties about whether it can deliver the clean skies promisedfor the world's top athletes.
The city's chronic pollution, a sometimes acrid mix ofconstruction dust, vehicle exhaust and factory and power plantfumes, has been one of the biggest worries for Gamesorganisers.
Beijing has ordered many of its 3.3 million cars off roadsand halted much construction and factory production in aneffort to cut pollution before the Games open on August 8.
But a sultry haze persisted on Monday, and state media saidBeijing might be forced to restrict more cars and shut morefactories if the pollution persists.
City officials had earlier said the haze was due to humidweather, not pollution. But state media on Monday suggestedGames organisers were also worried and considering morepollution cuts.
"More vehicles could go off the roads and all constructionsites and some more factories in Beijing and its neighbouringareas could be closed temporarily if the capital's air qualitydeteriorates during the Olympic Games," the China Daily said.
Xinhua said air quality in Beijing on Monday was Grade II,making it officially a "blue sky day" despite the grey haze,with the main pollutant being particulate matter.
Many athletes have delayed arriving in Beijing until thelast minute to avoid bad air and the International OlympicCommittee said it may reschedule endurance events to preventhealth risks to athletes if pollution is bad.
Marathon world record holder Haile Gebrselassie has alreadypulled out of the marathon over fears of damaging his health.
On Monday, the Australian Olympic Committee said itsathletes would be allowed to withdraw if pollution poses athreat. "For us the athlete's attitude to the event isparamount," AOC vice president Peter Montgomery told reporters.
For four days up to Monday, Beijing had not experienced a"blue sky day", when the pollution index meets the nationalstandard for "good air quality." Hong Kong, host of theequestrian events, was also badly polluted on Monday after aweek of clear, blustery weather.
A Beijing Environmental Protection Bureau official, Li Xin,told the Chinese-language Science and Technology Daily theemergency pollution plan is likely to come out this week.
Li said proposed stricter controls on vehicles andfactories also covered Hebei province and the port city ofTianjin, both next to Beijing.
UNUSUAL WEATHER
Zhu Tong, a Peking University professor advising Gamesorganisers on air quality, said an unusually long bout ofstill, humid weather was trapping in pollution.
"Although the restriction measures have reduce pollutionemissions, if weather conditions are not favourable todispersal, the build-up effect will be extremely considerable,"Zhu told the Science and Technology Daily.
Cars in Beijing are now banned on alternate days dependingon their licence plate number -- odd or even -- and manygovernment cars have been ordered off the roads. Taxis, busesand Olympic vehicles are exempt. Around Beijing, heavilypolluting factories, such as steel plants, also have beenclosed.
The city has invested billions of dollars in publictransport too, especially on upgrading and expanding the subwaynetwork, hoping to encourage people not to use their cars.
A spur line up to the main Olympic Green opened on Monday,Xinhua news agency said, which will feature airport-likesecurity checks.
A city environment official said last week that air wasimproving, with a 20 percent cut in carbon monoxide, nitrogendioxide and particulate matter since the same time last year.
But Greenpeace gave Beijing a mixed assessment. It notedenergy-saving technology in Olympic venues, stricter vehicleemissions standards and expanded public transport.
But it said clean-up efforts were hampered by lack ofpolicy transparency and independently verified data. Beijingdid not even officially collect statistics on smallerparticulate matter and ozone, pollutants that worry healthexperts, Greenpeace said.
"Beijing has also missed a golden opportunity in using theGames as a platform to implement more ambitious initiatives,"said Lo.
(Additional reporting by Guo Shipeng and Ben Blanchard inBeijing and Andrew Stevens in Brisbane; Writing by Nick Macfie;Editing by Sanjeev Miglani)
(For a video of latest smog conditions, seehttp://www.reuters.com/news/video?videoId=86131&videoChannel=74.
For more stories visit our multimedia website "Road toBeijing" at http://www.reuters.com/news/sports/2008olympics;and see our blog at http://blogs.reuters.com/china)