In 1998 the World Resources Institute (WRI) and the US Environmental Protection Agency (EPA) Office of Policy entered into a multi-year Cooperative Agreement CR826980-01: Climate Policy, Air Pollution and Public Health: Estimating Mortality and Morbidity From Fossil Fuel Consumption in Major Urban Areas in Developing Countries. The broad goal of the project was to address the climate change, air pollution and public health implications of energy use in major urban areas, especially the very large 'megacities', of developing countries. The project activity was organized around studies with developing country experts to document the co-benefits that would follow from adopting less carbon-intensive energy and urban transportation policies in order to: (a) lessen the impact of greenhouse gases from fossil fuel combustion, and (b) significantly reduce current and future public health impacts from exposure to combustion-related air pollutants. This involved the development and adaptation of methods, working with technical experts in the target countries, and technical support to these experts in carrying out the assessments. In addition, results of the methods development, case studies and other technical information were synthesized and disseminated to a variety of important audiences including the relevant technical communities (e.g., health researchers, air quality management officials), policy makers, and the interested public. During the roughly four year duration of this project, the cooperative agreement was amended twice and the scope expanded to include assessment of a broader range of ancillary effects (co-benefits or costs) of climate change policies, and development of corporate level green house gas inventory methodology.