The concept of sustainable development has become very much "en vogue" in the past decade.We have also observed a shift in the interpretation of this concept from a global perspectiveto a meso perspective, i.e. a local, regional or sectoral level.This paper aims to highlight the urban dimension of environmental issues. After a sketch ofurban pollution problems and of economie analysis tools, the notion of urban sustainabilitywill be advocated as a meaningful analytical and policy concept. Next, the main focus ofthis paper will be on a typological approach to urban sustainability issues on the basis ofthree characteristic angles, viz strong and weak sustainability, absolute and relativedecoupling and the spatial ecological footprint. Various methodological issues will also bediscussed, while the paper will be concluded with some policy perspectives.