Is there more than one type of pollution?

Yes, there is. There is water pollution, air pollution, and much more.

Minor differences in different areas (they are found over most of sub saharan africa) but not distinct enough to be sub categorised.

Serious depression comes in two varieties: unipolar and bipolar. When you have bipolar disorder, you experience both depression and episodes of mania (extreme states of agitation, hyperactivity, euphoria, marked irritability, decreased need for sleep, racing thoughts, and sometimes psychotic symptoms) or hypomania (milder episodes of increased energy, euphoric mood, and decreased need for sleep). Unipolar depression involves only depressive episodes, never mania or hypomania.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.