Introduction 

        "The houses are made of mud and they're very crowded. And the slum very dirty ,you can see."

(By Sheri Fink).The most population place in the world is slum.The existence of slum affects human populations because the people do not live in strong houses ,slum create an increase in population ,and the dirty conditions lead to diseases. Many people that live in slums do not live in a strong house.