Every day 1.8 billion children breathe air that is so polluted it puts their health and development at serious risk. In 2016, 600 000 children died from acute lower respiratory infections caused by polluted air. A new report of the World Health Organization on Air pollution and child health: Prescribing clean air examines the heavy toll of both ambient (outside) and household (indoor) air pollution on the health of the world’s children. The report is being launched on the eve of WHO’s first ever Global Conference on Air Pollution and Health held at WHO Headquarters in Geneva on 30 October - 1 November 2018.