The world environment means simply what is around us. Some people live in towns, other in the country. There are a lot of ecological problems.
The most serious ecological problems are: noise from cars and buses; destruction of wildlife and countryside beauty; shortage of natural resources; the growth of population; pollution in its many forms.
For example water pollution: water is everywhere, but there is no ocean or sea which is not used as a dump. Many rivers and lakes are poisoned too. Fish and reptiles can't live in them. People can't drink this water. So we have to clean the water environment. But it is not the only problem with pollution.
Another problem is air pollution. Air pollution influences the health of people. There are a lot of dangers. For example: ultraviolet radiation from the sun can cause skin cancer. Normally the ozone layer in the atmosphere protects us from such radiation, but if there are holes in the ozone layer ultraviolet radiation can get to the earth. Many scientists think that these holes are the result of air pollution.
Also we have problem with nuclear pollution. Nuclear pollution cannot be seen but its effect can be terrible. To make air clean again we need good filters at nuclear power stations, at factories, in cars and buses.
Another problem is growth of population. They don't have enough places to live. They need more water, more food. So it is the reason of the shortage of the natural resources. It is very difficult to solve this problem.
Also one of the most serious problems is green house effect. It works like this: sunlight gives us heat. Some of the heat warms the atmosphere and some of the heat goes back into space. Nowadays the heat can't go into space. That's why winter and summer temperatures in many places have become higher. If the temperature continue growing up the snow on the mountains and ice will melt, so the most of the earth will be under water.
So every person has to understand how important it is to solve this problems, that endanger people's life. For example I try not to throw out in our city.