"Marathon is innocent and, as an aerobic exercise, it has high demand for outdoor air condition.

"We believe China's Government will make more efforts to control the pollution, focus on air surveillance and forecast the weather for local people."

Heavy smog over the Christmas period, including here in Shanghai, has fuelled Lamine Diack's concerns ©Getty Images

An IAAF spokesmen reiterated Diack's comments to insidethegames and insisted that the organisation's views had changed little since their stance during the 2006 World Junior Championships in Beijing and the Olympic Games two years later when concerns were also voiced.

In 2008, despite international condemnation ahead of the marathon races, Kenya's Samuel Wanjiru exacerbated these fears by winning in a stunning Olympic record time of 2 hours, 6min 32sec as smog levels were lower than forecast.

But with official data showing that 2013 has had the most smoggy days of any year in China over the last 52 years, the problem is not going to disappear. 

Since the beginning of December, at least 25 regions and provinces across the country have reported high pollution levels, particularly of PM2.5, which are tiny floating particles measuring 2.5 micrometres or less in diameter.

PM2.5 particles are especially hazardous as they can settle in the lungs and cause illnesses, such as respiratory problems, and tension is growing across China to remedy the problem.

Air pollution issues also impacted other sporting events in 2013, with the Hockey World League Semi-Final being "monitored" by the International Hockey Federation (FIH) due to concerns, although the event did eventually go ahead. 

The smog did little to stop Samuel Wanjiru from winning the Beijing 2008 Olympic marathon in record breaking fashion, but the problem appears to be getting worse ©Getty Images



Elsewhere, Diack was positive about the growth of athletics in China - after the country won four medals at the 2013 World Championships in Moscow, including two on the road in race walking events.

A total of 44 marathons were staged in China in 2012, up from 22 in 2011 and, according to the Chinese Athletics Association, even more races are planned for 2014.

"It was in the 1970s when I came to China for the first time - all these years passed - I'm a witness of China's development of sports, especially in city marathon," Diack said.

"The increase of races and participants shows that the sport has become more and more popular."

Diack also said that Chinese athletes and coaches should strengthen contacts with the top teams in track and field, such as Kenya, Ethiopia and Jamaica, as well as with other top marathon city races.

"The haze should not curb the marathon race and the cities' managers should not slow down the pace to promote the sport," he added.