'The pollution in China is a threat to my health and it would be difficult for me'

The marathon world record holder Haile Gebrselassie has said he will not compete in the event at this year's Beijing Olympics because of concerns about the city's high levels of air pollution.

The Ethiopian runner suffers from asthma, and the condition forced him out of last year's London Marathon. Gebrselassie will instead compete in the 10,000m event in Beijing.

"The pollution in China is a threat to my health and it would be difficult for me to run 42km in my current condition. But I am not pulling out of the Olympics all together," Gebrselassie told Reuters.

Beijing has such high pollution levels that spectators intending to visit the Olympics have been advised to undertake only limited exercise while in the city.