Air pollution can 1. be defined as the addition of something harmful to the air at a faster rate than it can 2. be absorbed. Everyone should be concerned about air pollution. It 3. affects us all and as it 4. continues to worsen, so the environmental impact increases.

One of the major causes of air pollution in cities is car use. Cars 5. are used for even the shortest of journeys, and all efforts by governments to encourage people 6. to use public transport seem to be failing. Industry is another major cause of pollution in our cities, but fortunately new industrial sites 7. are being built away from large urban centres.

It 8. is said that there are too many contributing factors for us 9. to decide exactly which one is the main problem but I believe that one of the most serious problems that needs 10. to be tackled is the use of the car. In some cities, laws 11. have been passed concerning car use. Others, for example, only 12. allow a certain number of cars into the city centre each day. In my opinion, this is a good idea. With this kind of law, people have no choice and 13. are forced to use buses and trains. This ensures governments 14. know that public transport 15. will be used, and can therefore justify the investment and expense of ensuring the system works properly.

Another thing government could do is to force people to have their cars checked for carbon emissions regularly.