составить вопрос к тексту There are over 150 super cities in the world with population from one to 15 million and more. Tokyo, New York, London, Mexico City, Rio de Janeiro and Moscow are just a few of the cities which have become super cities.

People in the super cities suffer from polluted environment: bad water, bad air and noise. A new term, urban climate, is used now for such cities. It means high temperature, oppressive atmosphere and intensive smog. Smog can make people feel ill and have difficulty in breathing. In Mexico City just breathing the air is life threatening. It is equivalent to smoking two packs of cigarettes a day. The same situation is in 600 cities of the former Soviet Union.

Air is polluted by the release of harmful substances, smoke from chimneys and exhaust fumes from cars. The problem is especially bad in some cities where there is no much wind and a brown layer of smog hangs in the air.

Some experts consider that it is practically impossible to protect the big cities from pollution. The World Health Organization (WHO) was studying air pollution around the world for over eight years. It measured two things: the level of sulphur dioxide (S02) in the air and the level of smoke. Sulphur dioxide and smoke pollute water and have serious effect on forest, buildings and health of people.

In the WHO report it is shown that the cities with the most considerable level of S02 in the air are Milan, Teheran, Prague, Santiago and Sao Paulo. However, the atmosphere in some cities with clean air gets worse in winter. Helsinki, for example, becomes one of the cities with the largest proportion of S02 in the air in winter. This must be connected with the heating of houses. One can also mention Glasgow and Warsaw which suffer in the same way.