Recent weeks have seen abundant pollution - of one form or another - steadily wafting down to Hong Kong from the north. If evidence from previous years offers any indication, this trend will continue for several months. But lest anyone think otherwise, a significant proportion of Hong Kong's filthy air is locally generated. Coal-fired power stations, diesel buses and the low-quality, high-sulphur marine fuels allowed through the container port all contribute to choking local smog conditions.

At one time, magnificent clear skies - which appeared from the Mid-Autumn Festival onwards - heralded the onset of Hong Kong's glorious autumn and winter. After months of relentless heat and humidity, residents breathed a sigh of relief.

Writers familiar with the colony all described the cooler months as Hong Kong's most pleasant spell. As recreational travel to the region steadily gathered pace from the 1950s onwards, autumn and winter became Hong Kong's international tourist season, with clear winter skies becoming a habitual theme in travel writing. Popular local author Austin Coates captured the feeling when he wrote of the "rare beauty of Hong Kong's winter days".

But things have changed. Choking smog blankets the city throughout this once-glorious season. On a bad day, one side of the harbour is invisible from the other, only a few hundred metres away at its narrowest point. Ongoing studies indicate Hong Kong's air quality is about three times worse than previously judged. One deep breath on any downtown roadside will make these pronouncements obvious to anyone with a functioning set of lungs, so let's continue to hope better environmental controls really are on the way, as promised.

The Tourism Board, somewhat inevitably, remains silent on local air-quality issues. Why would it be otherwise? Most of the city's visitor arrivals these days are from places on the mainland that regularly disappear from satellite maps due to their own appalling air quality. Few tourists from such places are likely to complain about the air they breathe here - quite the reverse. And what possible effect might a few visitors' complaints have anyway?

Mainland tourists might partake of whistle-stop, photo-opp tours, but they generally aren't coming to Hong Kong to enjoy the magnificent views that intermittently appear through the pall of smog. No, they come to shop for all the things - from branded goods to unadulterated foodstuffs - they cannot buy with much consumer confidence at home. An added benefit may be that Hong Kong's overall autumn/winter air quality is still - chokingly nasty though it is - significantly better than that of most other urban parts of China. But it's certainly not the main local attraction.

When Chinese astronaut Yang Liwei visited Hong Kong in late October 2003, he was taken to the lookout point over Tsing Ma Bridge. When he spoke of admiring the scenery through smog so thick that the other side of the Kap Shui Mun channel was invisible, many locals choked with amazement (as well as choking in the literal sense). Yang had to be "on message" while he was here - we all accepted this. And, in fairness, the air was probably clearer than in his Manchurian hometown. But, all the same …