The Ultra-Low Emission Zone (ULEZ) is a targeted initiative aimed at reducing emissions and car use in London, in order to help the city reach its goal of net zero carbon emissions by 2030. ULEZ targets the most polluting vehicles which emit the highest level of pollutants and greenhouse gases compared to newer vehicles, by setting stricter emissions standards for vehicles entering certain areas of London. This encourages drivers to switch to cleaner, more fuel-efficient vehicles, or to use alternative modes of transportation. Targeting the most polluting vehicles is considered the best way forward as it directly addresses the main source of emissions and helps to achieve the goal of ULEZ.