To meet climate change targets, the Government encouraged the uptake of diesel vehicles based on their lower CO2 emissions. However, NOx emissions from diesel vehicles vary so widely from their type approvals that air quality in cities across Europe has not improved as predicted. The best solution would be for a greater share of journeys done by foot, by bike, or on ultra-low emissions vehicles, but we recognise that this is not possible for all. Encouraging greener modes of transportation including electric vehicles or travel using public transport are options we are exploring as part of the Clean Air Plan package of measures.