Verbruggen, who is chairman of the Coordination Commission for the Beijing Games, said rapid economic growth brought additional challenge to Beijing's environment, which could not be foreseen seven years ago when Beijing was awarded the right to host the Games.

"I must say the Chinese totally lived up to the 130 commitments they made. They have achieved a lot improving the environment," Verbruggen told reporters at a news conference of the annual Sport Accord convention.

"But nobody could have foreseen seven years ago economic growth of double digit figures. Nobody could have seen the economic boost would have led to some four, five or six thousand construction sites," he said.

But Verbruggen said the Chinese capital were trying to solve the problem before the Games that would open on Aug. 8 next year.

He said the Chinese government is taking measures like dust control and closing down some factories which will undoubtedly benefit their cause.

"We are very confident the air quality at test events and at the time of the Games will be up to the levels that allow the athletes to have the best performance," he concluded.