Urbanization is an important index of socio-economic structure of a region as urban centers have special role to play in its development. In statistical sense, urbanization connotes to the ratio of urban population to the total population size, its characteristics and the administrative setup of a particular area. Statistics reveal that nearly half the world's population lives in cities. Between 1960 and 1992 the number of city dwellers worldwide rose by 1.4 billion. Most of this city growth has occurred in developing countries, where the number of people living in cities is increasing every year. Cities with more than 10 million inhabitants are known as mega cities. It is predicted that by 2015, 22 of the 27 mega cities would be in developing countries. Historically, the city was the place where arts and sciences were flourishing. Democracy was a new type of governance that found its seedbed in the city and still nowadays political power is largely concentrated in cities and governments have established their premises in cities. The administrative functions are usually executed in capital cities of countries. The city is the market place for economic activity.
The city brings together communication, competence and creativeness. Average wages and income for urban areas are higher than in rural areas, even making allowance for higher living costs in the cities. In developing countries today urban health conditions seem to be better than in rural areas. Higher life expectancy and low child and women mortality rate in the urban areas of developing countries sound like one of the blessings of urbanization. Education is a powerful motive for moving to the city. Rural education has often been neglected in favor of urban but it is also an essential urban function. Cities have always provided intellectual stimulus and educational leadership. In developing countries there is often substantially higher, proportion of educated people in the cities. Urban environments often encourage improvement in women's status. In negation of the view that city growth is bad and it aggravate social problems; the 'blessing' theorists hold cities as engines of growth for economies for millennia. Cities offer more avenues to break the vicious circle of poverty. It is of course an undeniable fact that a process of urban sprawl has taken place, but this phenomenon did not destroy urban functions, but on the contrary reinforced urban functions. The cities attract investments and tap the economic benefits of globalization. Urban growth gives rise to economies of scale. Large cities also provide big differentiated labor markets. This ongoing urbanization process has often been questioned by referring to the phenomenon of Over-urbanization, urban bias and the parasitic role of cities.
The most visible expressions of the problems of rapid urban population growth are the makeshift settlements on the outskirts of every city in the developing world. In most cities in developed countries the proportion of young people under 19 is less than 30 per cent of the population. Besides better mortality rates may simply be the result of more investment in the urban health sector - another example of urban bias. Although health in the cities may be better generally than in rural areas, the urban poor may be more at risk than their rural relatives. The world is on a path from which there is no return, transforming it into a predominantly urban planet. The transformation from a rural to an urban planet offers both great blessings and heavy burdens. The transition from agrarian to urban has always been considered a positive step, part of the process of modernization. However, the rapid growth of urban populations in societies rapidly changing in other ways is fraught with enormous tension and tremendously complex problems. Urbanization would be a blessing only when urban problems would be solved through economic efficiency and vast growth of productive forces.