Rural areas are important for urban areas because they provide labour for industrial development and for tertiary activities. At present, 47 per cent of the world’s six billion population lives in cities and more will join them in near future. This proportion is estimated to go up to 50 per cent by 2008. By 2050, an estimated two-thirds of the world’s population will live in urban areas, imposing even more pressure on the space infrastructure and resources of cities, which are manifested in terms of sanitary, health, crime problems and urban poverty.