The present work discusses the problems of atmospheric pollution of three Megacities of Latin America (Mexico City, Sao Paulo and Santiago). The environmental pollution control programs implemented by the Government are revised and the evolution of pollution levels during the period of 1988-1995 at Santiago de Chile and Sao Paulo, but until 1997 at Mexico City, in order to evaluate the impact of these programs. During this period, a decreasing trend is observed in the three cities in the levels of PTS, PM10, SO2, NO2, CO and O3, although most of these contaminants still exceed the air quality standards. It must be emphasized that the largest impact has been on the levels of SO2. We recommend the development of sustainable transport policies; in this context, various strategies were proposed by the Organization for Economic Cooperation and Development (OECD) in the European Conference of Ministers of Transport. Additionally, public participation is important when decisions are taken on transport policies.