¡¡¡¡According to a recent report by the UNEP1, if car numbers keep increasing at the present rate, there will be more than a billion on the road by 2025. Today, motor vehicles put out 900 million tonnes2 of carbon dioxide a yearª²ª²about 15 per cent of our total output. More vehicles will mean more global warming.

¡¡¡¡Also by 2025, twoª²thirds of the world's people will live in cities, so traffic jams and pollution will loom3 large in most people's lives. Worst of all will be the megacities4 of Asia. Beijing, Shanghai and Calcutta5 will each be home to as many as 20 million people, Bombay6 to 25 million.

¡¡¡¡Life in the country may not be much better. Asia is heading for a downpour of acid rain that will destroy forests and wither7 crops. The worst hit look like being Thailand, southeast China, northeast India and Korea, where economic growth is powered by fossil fuels8 rich in sulphur9.

¡¡¡¡Industrialised nations have reduced SO2 emissions. They have also cut production of CFCs10 and halons11, the chemicals that destroy stratospheric12 ozone. But the ozone layer is not yet safe. Under the Montreal Protocol, developing nations have until 2010 to cut production. There is still a black market in CFCs, and halon production has increased in countries such as Brazil, India and Mexico.