The major causes of water pollution are:

1. Industrial waste: Industries produce a huge amount of waste which contains toxic chemicals and pollutants which can cause air pollution and damage to us and our environment. They contain pollutants such as lead, mercury, sulphur, asbestos, nitrates and many other harmful chemicals.

2. Sewage and waste water: The sewage and waste water that is produced by each household is chemically treated and released into sea with fresh water. The sewage water carries harmful bacteria and chemicals that can cause serious health problems.

3. Mining activities: Mining is the process of crushing the rock and extracting coal and other minerals from underground.

4. Chemical fertilizers and pesticides: Chemical fertilizers and pesticides are used by farmers to protect crops from insects and bacteria’s. They are useful for the plant's growth. However, when these chemicals are mixed up with water produce harmful to plants and animals.

5. Animal waste: The waste produced by animals is washed away into the rivers when it rains.

6. Leakage from the landfills: Landfills are nothing but a huge pile of garbage that produces the awful smell and can be seen across the city. When it rains, the landfills may leak, and the leaking landfills can pollute the underground water with a large variety of contaminants.

7. The burning of fossil fuels: Fossil fuels like coal and oil when burnt produce a substantial amount of ash in the atmosphere. The particles which contain toxic chemicals when mixed with water vapor result in acid rain.