Since ancient times Nature has served Man, being the source of his life. For thousands of years people lived in harmony with environment and it seemed to them that natural riches were unlimited. But with the development of civilization man's interference in nature began to increase.
Large cities with thousands of smoky industrial enterprises appear all over the world today.
The by-products of their activity pollute the air we breathe, the water we drink, the land we grow grain and vegetables on.
Every year world industry pollutes the atmosphere with about 1000 million tons of dust and other harmful substances. Many cities suffer from smog.
Vast forests are cut and burn in fire. Their disappearance upsets the oxygen balance. As a result some rare species of animals, birds, fish and plants disappear forever, a number of rivers and lakes dry up.
Environmental protection is of a universal concern. That is why serious measures to create a system of ecological security should be taken. Some progress has been already made in this direction. As many as 159 countries — members of the UNO — have set up environmental protection agencies.
The international organisation Greenpeace is also doing much to preserve the environment.