Waste products can generally be classified as follows:
Certain bacteria break down biodegradable wastes to non-poisonous substances. These wastes should be properly and efficiently treated. Sometimes biodegradable wastes are recycled. Taking for example, cow-dung may be used for the preparation of gobar gas which gives us heat and light. Compost is another use of recycling biodegradable wastes.
But under non-biodegradable wastes, D.D.T., plastics, aluminum wastes etc. are major pollutants. These cannot be made less toxic easily.
Steps should be taken to reduce pollution caused by the smoke etc. of vehicles and industries.
Radio-active waste is a dangerous pollutant. It should be handled properly and efficiently.