The Importance Of Urbanization

The world is undergoing the largest wave of urban growth in history. More than half of the world’s population now lives in towns and cities, and by 2030 this number will swell to about 5 billion. Much of this urbanization will unfold in Africa and Asia, bringing huge social, economic and environmental transformations (UNFPA) [1]. Urbanization is accompanied by a number of challenges arising from population concentration in metropolitan cities; environmental degradation has occurred very rapidly and causing a shortage of basic needs, worsening water quality, air pollution and problems of disposal solid wastes and hazardous (Cronin 2012) [2]. Environmental decay in a city is essentially caused by rapid urbanization and the mismatch in the provision and maintenance of housing and infrastructure. These include exposure to lead, air pollution, traffic hazards, and the "urban heat island" amplification of heat waves. As the number of urban consumers and their material expectations rise and as the use of fossil fuels increases, cities contribute to the large-scale pressures on the biosphere

Upgrading process is a multi-sectorial operation that integrates environmental, economic and social interventions. It matches with the aim of sustainable urban development of creating healthy, economically urban communities that are socially just in terms of their access to better services and improved urban environment. Upgrading also economizes resource utilization by relying on existing efforts and structures. The sustainability of urban development is more ensured when local residents have a greater sense of ownership of their locality and the improved services, which is more evident in existing informal areas and should be enhanced through upgrading