In the modern world, different forms of polution take oxygen from the air, rivers and oceans. In our cities, vehicles and factories swallow oxygen, and their fumes poisons the air with carbon dioxide. This urban pollution spoil the air we breathe. It is the major cause of diseses such as lung and skin cancers. If nothing is do to reduse carbon dioxide emissions, most of us will died of these diseases. In the countryside, fertilisers wich contains phosphorus and nitrogen spill over into rivers. As a result, fish is dying in increasing numbers, and aquatic life is sufocating from lack of oxygen.