Despite huge efforts by the Chinese Government to clean up Beijing, the air is still thick with pollution in the city and a mist of dust particles hangs over the track in the Olympic stadium. Construction grime chokes the throat and a layer of dust coats the seats in the “Bird's Nest” stadium, the surrounding moat and the newly planted flowers on the Olympic Green.

With visibility on some days reduced to about 300 metres, Chinese officials are trying desperately to find ways to reduce the smog before the Games start in August.

There is also mounting concern about traffic congestion, with more than 1,300 new cars joining the 3.5 million vehicles already in the capital every day. The 20-mile trip to the Olympic stadium from the centre can take more than 90 minutes and despite roads being built to get access to the Green, the area is congested.

Officials set a target last year to reduce the number of cars by a million before the Games begin and the latest plan is to allow residents to use their cars only on alternate days. The proposal, piloted last year is to let cars with odd-numbered plates drive on odd-numbered days and even-numbered cars on even days. If drivers use their car on the wrong day they risk being stopped by the police, fined and told to drive back.

Beijing residents are also being told to make plans to leave the capital in August while the Games are being held unless they are directly involved in the Olympics.

The escalation in car numbers on the roads is because they are now much more affordable. Those on average salaries of £5,000 to £6,000 a year in the business community can afford the £1,500 cost for a standard car, according to a local official guide.

Special permits are also being planned to discourage visitors from Chinese provinces outside Beijing from coming into the city. Any groups of Chinese tourists or business people visiting the Games will have to be invited by the Government. More than 3 million visitors are expected in the capital to add to its 15 million population, including 20,000 to 30,000 Britons.

The Government is determined to meet green guidelines set by the IOC and cars being manufactured have to meet strict emission criteria. The authorities are also suspending construction works and closing or relocating heavily polluted industrial plants from July to help to clear the air.

Digging and pouring of concrete on construction sites are to be suspended from July 20 to September 20 and 19 heavily polluting factories have been ordered to reduce their emissions in the same period by 30 per cent.

Beijing has spent more than $15billion (about £7.6billion) to clean up the city for the Olympics. Green measures include switching from coal to gas, closing and relocating big polluters, fining building sites causing dust pollution and recycling water. The Government claims the measures are having an impact on the city with more “blue-sky” days last month than at any other time in the past eight years.