Preparations for the Beijing 2008 Olympics are well on schedule but pollution is still a concern, the International Olympic Committee said on Wednesday.

Following a report by the Beijing Games organisers and the IOC chief inspector Hein Verbruggen, the IOC said work was still needed to improve air quality in the Chinese capital.

"The important thing for us is to understand exactly what it is...and to understand what it will be at the time of the Games," he said.

Earlier Verbruggen told reporters environmental pollution was an issue that needed to be addressed.

"Environment is certainly an issue but they (Chinese organisers) are looking into it," said Verbruggen. "A lot of things are being done. We still remain confident."

He said the sheer size of the country and the rapid economic growth was adding to the problem.

Verbruggen added Beijing had committed itself to more than 350 steps to improve the environment, backed by a budget of $12.3 billion, and so far was working on every single one of them.

"There were 350 commitments made and we cannot find one they do not live up to," he said.

In their progress report to the IOC Executive Board in Kuwait, Beijing Games organisers said they had specific measures which will come into force in order to improve air quality ahead of the Olympics.

They said thousands of taxis and buses with "excessive emissions" would be replaced and the large Shougang steel plant in Beijing would cut steel and coke production by 50 percent by 2007.

"They (Chinese organisers) also talked about relocation and renovation of polluting industries and a plan for an intensified air quality at Games time and that is what they are studying with the University," said IOC Director of Communications Giselle Davies.