Atmospheric Pollution and Human Health in an Indian Megacity is a four year research programme jointly funded by the Natural Environment Research Council (NERC), the Medical Research Council (MRC), the Newton–Bhabha Fund, and the Ministry of Earth Sciences (MoES) and Department of Biotechnology (DBT). Urban air pollution is a severe problem in India with significant impacts on the economy and the health of the population. This programme, which has been organised into four interrelated themes, will support research on the sources and emissions of urban air pollution in New Delhi, India, the processes underlying and impacting on these, and how air pollution then impacts on health. Existing and new findings will be combined to understand the cost-effectiveness of potential interventions and thus identify appropriate solutions for the benefit of the economy and population.