Sports marketing insiders have called for a weather warning system for sports events in China after the Beijing Marathon took place in heavy smog on Sunday.

Thousands of runners battled thick smog at the marathon, with some athletes donning masks as air pollution soared to 13 times the maximum recommended level. Some runners reportedly cancelled altogether.

Yao Zhenyan, vice president of Oceans Marketing, a sports marketing firm in Beijing, questioned why there are no measures to handle sports events when heavy pollution occurs.

The Beijing Marathon's organizers said in a post on Sina Weibo that it would have been "very difficult" to postpone the race, as "46 percent of the athletes are from other countries or regions outside Beijing."

Organizing an international sporting event involves many factors, and there are legal issues connected to postponement, explained Zhang Zhenpeng, the organizer of the Americas' Super Derby and general manager of Beijing-based Inter Sports.

After running the Beijing Marathon, Zhang said he hoped the city government would issue a weather warning system to avoid harming people's health.