Pollution: What is it?? How does it occurs??

 What is Pollution? 

Pollution is the undesirable change in the physical, chemical or biological characteristics of the air, water or land that can harmfully affect the health, survival or activities of humans or other living organisms.

How does it occurs??

Unwanted chemicals or other materials found in the air can harm health, environment and property. Many air pollutants occur as gases or vapours, but some are very tiny solid particles: dust, smoke that can cause serious health problems.

Pollution can take two major forms: local and global. In the past, only local pollution was thought to be a problem.

For example coal burning produces smoke, which is sufficient concentrations can be a health hazard in a particular locality.

One slogan, taught in schools, was " The solution to pollution is dilution." The theory was that sufficiently diluted pollution could cause no damage. 

The twentieth century has seen population approch crisis proportions throught the world. At issue is the capacity of the bio sphere to disperse, degrade and assimilate human wastes. The biosphere is a closed ecological system with finite resources and is maintained in equilibrium by grand scale recycling. Awareness of both kinds of pollution, among other things, has led to the environmentalism movement, which seeks to limit human impact on the government.

Conclusion

In a recent decades, awareness has been rising that some forms of pollution pose a global problem. For example, human activities (primilarly nuclear testing) has significantly raised the levels of background radiation, which leads to Human helath problems all over the world.