China claims pollution success as skies clear

China claimed success on Tuesday in its pre-Olympic battle against Beijing's infamous pollution, as strong winds helped clear the thick smog that has hung over the Chinese capital this month.

Pollution levels have fallen by at least 20 percent since the first of a raft of short-term measures began at the beginning of July, Beijing Environmental Protection Bureau deputy director Du Shaozhong told reporters.

Despite visible signs of heavy smog that had pervaded Beijing in recent weeks and some branches of China's state-run press highlighting the pollution problems, Du insisted there had been 25 days of "clean air" in July.

"We have seen comprehensive measures implemented already and we have seen that they have had comprehensive results," he said.

Australian Olympic officials have told athletes they can withdraw from events in Beijing with no repercussions if they are concerned about pollution levels, it was reported Tuesday.

Australia's deputy head of mission Peter Montgomery said athletes would not be forced to compete, the Sydney Morning Herald reported.

Montgomery emphasised that he expected the country's 433 team members would choose to compete but any decision not to would be respected.

"It is extremely unlikely an athlete will not compete, most athletes train for 10 years for this moment," Montgomery said.

"For us, the athletes' attitude to the event is paramount. If they don't want to compete, that is fine. They will be under absolutely no pressure to compete if they feel uneasy or don't want to compete."

Nevertheless, Du confirmed that further emergency measures were being planned if pollution was a concern during the Games, which start on August 8.

"If we still don't have ideal air quality for the Games, we will take more measures, and they will be measures that are similar to what has already been taken but to a higher degree."

In the most dramatic of the recent anti-pollution steps, one million of the city's 3.3 million cars were taken off the roads on July 20, and more than 100 heavily polluting factories and building sites were closed down.

As Du gave his press conference on Tuesday morning, the skies of Beijing were much clearer than in recent weeks, thanks partly to a strong breeze blowing through the city that began overnight.

The heavy smog had reduced visibility to a few hundred metres (yards) on Monday, raising pressure on Beijing's Olympic organisers who had promised to stage a "Green Games".

The heavy smog had made international headlines because Olympic athletes began arriving in Beijing on Monday amid the thick haze -- highlighting the race against time to fix the problem.

Du said the winds in Beijing were three times faster on Tuesday than the previous day, and the air quality index had shown an improvement.