According to the UN-Habitat, half of humanity now lives in cities, and that the urban population will increase to 60% within next two decades. Developing world with highest growth rate of urban population absorbs on an average about 5 million new urban residents every month and thus
accounts for 95% of the world’s urban population growth. Urban growth is a result of a combination of factors namely geographical location, natural population growth, rural-to-urban migration, infrastructure development, national policies, corporate strategies and other major political, social
and economic forces.