Poor air quality is estimated to cause approximately 40,000 premature deaths a year in the UK. The UK is bound by EU laws that regulate air pollution, in particular the 2008 ambient air quality directive 2008/50/EC. In recent years greater attention has been drawn to pollution levels in urban areas, particularly nitrogen dioxide (NO2), the most common source of which are diesel engine road vehicles. A number of legal cases have been brought against the government, challenging their proposed plans to reduce emissions and the speed at which the plans will be implemented. This briefing summarises the provisions in the ‘Clean Air Zones Framework’, published on 5 May 2017, at the instruction of the High Court. The Framework provides guidance for local authorities in England when establishing both charging and non-charging zones, and sets out the permitted vehicle emissions standards. The briefing also summarises the reaction to the proposals, and the general election manifesto commitments made by the main political parties on the subject of air pollution.