1/ Many of the factories and plants produce waste and poured its into the rivers. So river`s water become poisoned.
2/ Holes in the ozone layer are very dangerous for the people: ultraviolet radiation passes through its and reaches the Earth. Such radiation can causes serious illness.
3/ The population of many countries suffers from a lack of water.
4/ Nuclear weapons is able to produce terrifying destruction on our planet.
Nuclear power stations are not so " clear " as some think: it causes of radioactive contamination.
5/ The environment is everything you see around you. Nowadays people comprahend that it is necessery to keep it clean, if the mankind wants to survive.