Air pollution is a very serious problem in many countries. It is caused by two main factors: the growth of industries and the increase of traffic on the roads of cities and towns. 
Production lines at factories and plants produce a lot of harmful gases that are discharged into the atmosphere. And the growing number of cars and trucks (lorries) in the cities also adds to the contamination of the air in urban areas.
As a result, people begin to suffer from lung disorders that may eventually cause lung cancer and other serious health problems.

What can people do to lessen the negative impact of air pollution on their health? First of all, people should make sure that industrial facilities comply with environmental laws and regulations. All factories and plants should have reliable scrubbers (filters) to prevent poisonous gases from getting into the atmosphere.
And people should try to decrease the number of cars on their roads by using public transport more. They can also help to solve the air pollution problem by planting more trees and shrubs within their cities and towns.