Cities have been around since the 3rd millennium B.C. And as long as they have existed, people have been drawn to them for what they offer. As recently as 1800, however, only 2 per cent of the world’s population lived in urban areas. Today, with 6 billion people on earth, slightly less than one-half live in cities and towns; by 2007 one half of them will. In the century ahead, urban centers are expected to expand to sizes never before seen. In the last 50-year period, the number of cities with more than one million inhabitants increased more than fourfold — from 80 to 365.
From the 20th century, the world is experiencing a strong trend of rapid and massive growth of cities as well as migration from the rural areas towards the urban ones. As the wheel of human civilization is moving forward, people are leaving agriculture based rural society to industrially developed towns and cities. The global flow of people from rural areas to urban areas is increasing significantly day by day. According to the United Nations, half of the world's population is living in urban areas right now.
This trend or sociological change, which leads people to leave their age old living places and forces them towards the urban areas, is generally called urbanization. It includes the physical growth of urban areas as well as the rush of people from the rural areas to those urban ones. Every single developing country is going through rapid urbanization; and the developed ones have already gone.
According to some estimates, by 2030 the proportion of people living in cities globally will reach 61%, with almost 80% of urban dwellers living in less developed countries. It also appears that most of the world population growth will be absorbed by cities of the south over the next fifty years. The increasing pace of urbanization has reached such a level that it has become an inseparable part of civilization in 21st century. The triumph of urbanization is at such a stage...