what is pollution its types their sources and effects

Pollution is the introduction of contaminants into natural environment that causes adverse changes

mainly there are 4 types of pollution...

air pollution , water pollution , noise pollution and soil / land pollution. 

However, they can be further subdivided. 

Air pollution:- the main sources of air pollution is factories and vehicles 

water pollution is mainly caused by human activities like the usage of detergents and other non biodegradable substances. Water is usually polluted by the industrial effluent which is directly released in water. 

Noise pollution :- Loud speakers, D.J, horns etc. 

Land pollution :- usual source of land pollution is harmful fertilizer and untreated waste.