Air pollution is a leading cause of death and disease globally, accounting for over 4 million deaths annually. Polluted air, containing small particulate matter and dangerous gases such as Sulphur dioxide and nitrogen dioxide, causes respiratory and cardiovascular disfunction, and has also been associated with an increasing risk to cancer.

Urban areas are particularly affected by air pollution because of high population density, proximity to industries, and high levels of vehicular emissions.

Air pollution is also causing fundamental changes in our environment and contributing to climate change which has multidimensional impacts on people's health.