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Beijing's Olympic shutdown begins today, a drastic plan to lift the Chinese capital's grey shroud of pollution just three weeks before the games.
Half of Beijing's 3.3 million vehicles will be pulled off the roads and many polluting factories will be shuttered. Chemical plants, power stations and foundries
left open have to cut emissions by 30 per cent - and dust-spewing construction will be halted.
In a highly stage-managed Olympics, aimed at showing off the rising power of the 21st century, no challenge is greater than producing crystalline air for 10,500 of the world's greatest athletes.
"Pea-soup air at the opening ceremony would be their worst nightmare," said Victor Cha, head of Asian Studies at Georgetown University.
Striking venues and US$40 billion ($53 billion) spent to improve infrastructure cannot mask Beijing's dirty air. A World Bank study found China is home to 16 of the 20 worst cities for air quality.
Three-quarters of the water flowing through urban areas is unsuitable for drinking or fishing.
International Olympic Committee president Jacques Rogge has repeatedly warned that outdoor endurance events lasting more than an hour will be postponed if the air quality is poor.
Under the two-month plan, vehicles will be allowed on the roads every other day depending on registration numbers. Also, 300,000 heavy polluting vehicles - ageing industrial trucks, many of which operate only at night - were banned from July 1.
Five days after Sunday's traffic ban goes into effect, special Olympic traffic lanes will begin operating until September 25. This plan has been used in previous games. Beijing is setting aside 265km of roadway, where certified Olympic vehicles will be allowed to move from hotels, Olympic venues and the Athletes Village.
To further ease congestion, employers are being asked to stagger work schedules. Public institutions will open an hour later than normal.
Two new subway lines scheduled to open today should also bring relief.
Line 10 is a 25km stretch than runs from southeast to northwest across the sprawling city. Line 8 - the Olympic Line - is a 5km spur line with stops at central Olympic venues. A third rail link also is set to open today - the 28km airport line, which runs to the city centre.
Officials say Line 10 will shuttle 850,000 passengers daily during the Olympics. The Olympic venue line is expected to carry about 220,000 with the airport line serving 30,000.
The plan to clean the grey air seems to match the high-security tone of the games, which will be policed by 100,000 officials. Razor-wire barriers and soldiers standing at attention guard the outskirts of the Olympic Green area, and the Chinese have even installed ground-to-air missiles near one Olympic venue to protect it from possible attacks.
