Diesel pollution have been increasingly shown to be extremely harmful to public health and are estimated to contribute significantly to the damage from urban air pollution. High emissions are caused by a number of factors. Some are technical, such as low fuel quality and old vehicle technology. How countries are trying to tackle diesel emissions, lessons that can be learned from industrial as well as developing country experience, and what needs to be changed to better tackle air pollution from diesel vehicles will be explored. A cross-sectoral and multi-prong approach, whereby the knowledge base about diesel emissions in developing countries is expanded while examining interactions with transport, environment and energy sector policies, will be discussed.