On 7 September 2024, the world will celebrate International Day of Clean Air for blue skies calling for global action to combat air pollution, one of the greatest health and environmental challenges of our time. The day invites us all to consider how we can support action for clean air in our countries, cities and businesses, and make changes in our daily lives to reduce air pollution. These actions benefit human health, protect ecosystems, and reduce climate-warming air pollutants and greenhouse gases.