Some days the air quality in Beijing is so poor you can hardly see beyond the end of your gas mask.
As skylines disappear into the murky, noxious atmosphere the city's pledge to deliver a 'Green Olympics' sounds increasingly hollow, but it would be wrong to write it off as a lost cause.
Over the past couple of decades the environment has been merrily slaughtered at the altar of China's economic boom. Sixteen of the world's 20 most polluted cities are on the mainland, with Beijing always in the running for the infamous top slot.
The European Satellite Agency recently named the capital as having the world's highest levels of nitrogen dioxide, a gas that is pumped out of exhaust pipes, power plants and factories, and which can cause fatal lung damage. Levels are up 50 per cent on a decade ago and still climbing.
The prospect of wheezing marathon runners being carted off to hospital isn't exactly the kind of PR the hosts are hoping for, so drastic measures are currently being cooked up to clear the skies.
To be fair, huge efforts and resources have already been ploughed into the environmental project over the past few years.
