Despite a series of campaigns led by international organizations to increase access to basic infrastructure and services in the last several decades, the number of urban residents lacking such access remains high both in the U.S. and developing countries.  For example, almost half of urban residents in developing countries currently do not have piped water in their homes, and a third lack access to sanitary toilet facilities.  The consequence of these and other problems are poor health, a lack of economic opportunity, and inadequate environmental conditions.