This strategy features in the framework of Agenda 21 as formulated at UNCED (Rio de Janeiro, 1992), now coordinated by the United Nations Commission on Sustainable Development and implemented through national and local authorities.
It has been increasingly recognized during the 1990s that data on human settlements in the European Region are incomplete and that comparing countries and cities is difficult because the statistics are incompatible. The sectors in which greater efforts need to be made to overcome the missing-information syndrome include homelessness, mental health, noise and the generation, collection and disposal of waste. In relation to urban health, noise is a commonly cited problem, homelessness is a high priority for about 30% of all Member States and waste collection and treatment pose environmental and health problems in the CCEE and NIS.