A major challenge for mankind is an informed respose to unprecedented urban growth and the intelligent mangement of urban settlements. The 20th century began with perhaps a dozen cities of 1 million resisdents; it will end with several hundred cities of that size, including about 30 urban areas with population exceeding an arbitrary threshold of 8 million. Most of today's cities provide neither equilibrium with the enviornment nor stability for its citizens. Ever since the the concept of sustainable development became widely known through the 1980 World Conservation Strategy and 1987 report of Burndtland Commision, it has been dismissed, ignored and forgotten about as far as most major cities are concerned. Many cities have long records of inadequate or ill-advised planning, or in some cases no planning at all. The result is often poverty, inadequate housing, contaminated or depleted water supplies, air pollution, and other forms of environmental degradations. Still the id!
             ea of a sustainable city is not out of reach and in some cases have been truned into a reality. Now, more than ever before, city governments in alls parts of the world are seeing the need to plan their policies and the use of the land under their control carefully.
             An enviornmentally non-sustainable city would consist of activities which require continual inputs of non-renewable resources, using renewable resources faster than their rate of renewal, causing cumulative degradation of the environment. Although the idea of cities was first intended to be for people to have a better standard of living, good social benfits, and have a sustainable enviornment, it has, in many cases fail to do so.
             In the cities of the developing world, turning on a tap for clean drinking water is a luxury because their populations have increased too rapidly for the supply of piped water to keep up with the deamnd. For example, in Manila, the capital of the Philippines, a typic...