1. Water pollution

2.  Humans have been polluting water as long as they have been on the planet.  Low levels of pollution are harmless, as water can clean itself by bacteria, fungi and oxygen.

3. Water pollution  However, there are limits to the water and its self-cleaning powers. Many waters have been severely polluted.

4. Water pollution  An Act to protect the water was adopted in the Netherlands in 1970. It stipulates that the provincial authorities are responsible for water pollution.  Expensive water treatment plants have been built to clean the water. Regulations have been introduced which ban the discharge of toxic substances by factories and households. As a result, many rivers have become much cleaner.

6. Water pollution  Many poor countries (LEDCs) use rivers for their drinking water, to do their laundry and as a sewer. This dirty water causes many diseases.