Pollution is derived from Latin word ‘polluere’ which means ‘to contaminate’ any feature of environment. Pollution is the effect of undesirable changes in our surroundings that have harmful effects on plants, animals and human beings. This occurs only when short term economic gains are made at the cost of long term ecological benefits of humanity. Environmental pollution is defined as an undesirable change in the physical, chemical and biological characteristics of any component of the environment (water, soil, air) that can cause harmful effect on various forms of life and property. Pollution can be primary (effects immediately on release to the environment) or secondary (product of interaction after release with moisture, sunlight, other pollutants etc.); pollution may be local, regional, transboundary or global. The agent which causes pollution is called pollutant.

Pollutants can be classified as:

1. Degradable or non persistent pollutants: These can be rapidly broken by natural processes. Eg. Domestic sewage, discarded vegetables etc.

2. Slowly degradable or persistent pollutants: These remain in the environment for many years in an unchanged condition and take decades or longer to degrade. Eg: DDT

3. Non degradable pollutants: These cannot be degraded by natural processes. Eg: Toxic elements like lead or mercury and nuclear wastes

Various types of pollutions namely air, water, soil, marine, thermal and noise pollution are presented here under