||This paper aims to identify environmentally harmful subsidies. After a brief reminder of the
consequences of market and government intervention failures, it reviews the definition and measurement of different types of support measures. It then gives a brief overview of the magnitude of subsidies in OECD countries and analyses the environmental effects of these subsidies, taking into account the interlinkages between the economy and the environment. It concludes with some considerations of the political, social and technical challenges associated with the phasing out of these subsidies. It does not claim to fully cover, nor to give a final answer to this very complex issue, but aims at providing a brief survey of the state of knowledge and main issues to be resolved. The issue of environmentally harmful subsidies will remain for a long time on the environmental, economic and political agendas.