In short, it would seem that helping cities to address their environmental problems can meet both poverty and sustainability goals, thereby contributing to sustainable development. This justification for giving a greater priority to urban environmental improvement assumes a relatively broad definition of urban environmental problems and a balanced strategy for addressing them. It depends on addressing a wide range of environmental problems. An emphasis on healthier sanitation in low-income neighbourhoods, on the other hand, will not reduce regional and global environmental burdens, since bad sanitation affects mainly people living in the vicinity. And neither will it do much to address the worst sites of ecological distress which, typically, involve industrial pollution of air and waterways.
Urbanization is a key component in environmental issues.
Problems can be defined in different ways, as well as their operational implications, especially for development assistance. Often, very broad definitions are used to justify assistance for addressing urban environmental issues, while most internationally sponsored urban environment initiatives conform to a far narrower definition. There is little coherence in how international agencies and others define the urban environment and identify its critical problems. However, several factors skew the operational definition of environment away from many of the central environmental concerns of the urban poor. A summary table shows the range of city-related environmental hazards by scale and type.