ABSTRACT
Cities transform environments and landscapes only within the built-up area but also for considerable distances. Most cities in Latin America, Asia and North Africa were important urban centres before the development of motorized transport. Acid precipitation is causing concern in the areas surrounding many cities in Asia and Latin America. However, care is needed in comparing the size of different cities' ecological footprints. No overview of environmental problems in Third World cities would be complete without some consideration of the impacts of city-based activities on the global commons. Cities require a high input of resources – fresh water, fossil fuels, land and all the goods and materials that their populations and enterprises require. Cities are also major centres for resource degradation. Water needed for industrial processes, for supplying residential and commercial buildings, for transporting sewage and for other uses is returned to rivers, lakes or the sea at a far lower quality than that originally supplied.
