The fog and mist that enveloped much of Sussex early this week was beautiful and almost romantic.

It rose out of rivers and damp fields, swirling its way on to hills and into towns.

There was, however, nothing lovely about the great smog of December 1952, which brought London to a standstill and which killed thousands of people, most of them elderly, who had respiratory diseases.

It is almost impossible to describe how thick and loathsome that smog was to people who have never experienced its like.

All traffic was slowed to a walking pace and conductors got out of buses to lead them forward, torches in hand.

You could not see across a narrow pavement and it was possible to get completely lost even near your home. You had to find familiar signposts and take your life in your hands crossing the roads.

The smog was yellow, grey or black. It was filthy. If you took a white shirt off, or blew your nose in a handkerchief, both would be covered with dirt. The smog blackened buildings and darkened the lungs of human beings.

That smog was the longest and worst in a line that went back to the Industrial Revolution more than a century earlier. Dickens knew smogs well and no one captured better their sinister atmosphere.

Smogs blotted out the sun so it was sometimes not seen in cities for a month. They could also cause clouds of dirt to be trapped under low clouds, on occasions making streets so dark during the day that street lights were switched on. Some people thought the world was about to end.

The Clean Air Act brought the end of the smogs remarkably quickly. The last great smog in London was 40 years ago and similar improvements were seen in other great cities such as Manchester and Birmingham, when most of the chimneys stopped belching out noxious smoke.

Even in Brighton, action had to be taken in the Sixties to stop pollution from smoke when the city authorities found the quality there was worse than in Sheffield.

Orders were made banning smoke-producing fuels in the central valleys while sea breezes were left to do their normal cleansing work elsewhere.

There is now a more insidious form of air pollution and it affects seaside resorts just as much as big cities. It is caused mainly by motor vehicles, whose use has increased almost tenfold since the great smog of 1952 but it is far less visible.

Occasionally on hot days you can see a dark shimmering haze over Sussex, especially when viewed from the Downs, but most people know about it only when they start wheezing and their eyes smart. The huge incidence of childhood asthma could well be related.

Measures are being taken to tackle this problem. The average car is far more fuel efficient than its predecessor half a century ago. On Brighton and Hove Bus and Coach Company buses, the newer models are so clean that you could put a handkerchief in front of one of the exhausts and it would remain spotless.

The best way to proceed would be to cut car use but only maverick politicians such as London Mayor Ken Livingstone will be bold enough to experiment with radical measures such as congestion charges. The next best solution is changes in fuel.

It is already possible to produce small runabout cars with battery power. Some vehicles run on liquid petroleum gas while progress is being made on using hydrogen as a fuel.

But the huge vested interests of car manufacturers and petrol companies are mitigating against swift progress.

As car ownership grows relentlessly and motorised Britain jams itself into gridlock, the air will become more noxious.

It will take the modern equivalent of that terrible smog half a century ago to make the politicians and public take action.