Urbanization is a key component of development, and often causes deterioration of environment. Growing population density and changing land-use patterns and lifestyles increase the burden on the environment. Along with rapid growth of population and industries, wastewater is discharged into water bodies without appropriate treatment; land-use change presents greater challenges of dispersed pollution origins; and the sound water environment is scarce. Once a city has grown and built in an inappropriate manner, it is difficult to change. Needless to say, water is essential to everyone, but rapid urbanization and industrialization together with climate change may result in serious problems in accessing safe water. It is therefore essential to incorporate environmental issues into urban policy. The Water and Urban Initiative is a new project of UNU-IAS which aims to contribute to sustainable development in Asia, focusing on developing countries. The project is supported by the Ministry of the Environment, Japan. Through this initiative, UNU-IAS seeks to provide policy tools and an information platform which assist developing countries in planning and implementing environmental policies for sustainable development. These policies should consider various aspects of development, such as population growth, urbanization, water treatment, and low-carbon technology.