Singapore ? Beijing’s heavy pollution may hurt the performances of athletes in this summer’s Olympic Games, although it will not endanger their health, International Olympic Committee President Jacques Rogge said Saturday.

The IOC in recent months has acknowledged the possibility that athletes’ performances may be affected by China’s pollution. But Chinese leaders have made repeated assurances that Beijing’s notorious smog will be solved before the Olympic Games begin.

“The health of the athletes is absolutely not in any danger,” Rogge said Saturday. “It might be that some will have to have a slightly reduced performance, but nothing will harm the health of the athletes. The IOC will take care of that.”

Rogge was asked to comment on the decision by Haile Gebrselassie, the world’s greatest distance runner, not to run the men’s marathon in Beijing because of worries over pollution.

“Haile Gebrselassie is arguably the best long-distance runner of the present generation,” Rogge said, adding however, the runner is “slightly asthmatic.”

Rogge was not ruling out the possibility that Gebrselassie could change his mind nearer to the date.

“He decided so far – I’m saying so far because we don’t know how things will evolve – not to participate in the marathon,” he said. “I would say, wait and see … when he sees the data that we are providing for them.”

Rogge had previously said outdoor events in August’s games could be delayed if the air quality was too poor.

Pollution had been a major concern for China and the International Olympic Committee in the leadup to the Aug. 8-24 Olympics. Some athletes are reportedly considering wearing masks to ward off the bad air in Beijing, while many will delay their arrival in China’s capital until the last possible moment.