Sweden The cities of Gothenburg, Lund, Malmö, Helsingborg, Mölndal, Uppsala, Umeå and Stockholm have low-emission zones. Heavy trucks and buses with compression ignited engines (mainly diesel engines) may not be allowed inside the environmental zones depending on their age and on their emission class. United Kingdom The London low emission zone came into effect in 2008 covering almost all of Greater London – the largest such zone in the world. London currently has levels of air pollution among the worst in Europe and road transport related emissions account for around half of total emissions of PM10 and NOx in the capital. The Low Emission Zone targets emissions of these pollutants from older diesel-engined lorries, buses, coaches, vans, minibuses and other heavy vehicles that are derived from lorries and vans such as motor caravans and motorised horse boxes. There was a phased introduction of the scheme from 2008 through to 2012. Different vehicles were affected over time and increasingly tougher emissions standards applied. The London Ultra Low Emission Zone started on 8 April 2019. In the context of the coronavirus pandemic, Mayor Sadiq Khan asked Transport for London (TfL) to suspend enforcement of the next phase of LEZ standards which had been due to come into force on 26 October, so that these would apply instead from the end of February 2021. Glasgow introduced a Low Emission Zone (LEZ) at the end of 2018. Initially, only local buses in the centre of the city are affected. The city council plans to extend restrictions to all vehicles, including older petrol and diesel cars, from December 2022. Norwich, Leeds, and York also introduced a LEZ. Since 2015, more than 60 local authorities have been ordered to tackle illegal levels of air pollution, which is why many of these planning to introduce clean air zones. The following cities have plans to introduce LEZs: Aberdeen (2020), Bath (2021), Birmingham (2019), Derby, Dundee (2020), Edinburgh (2020), Manchester (2022), Newcastle (2021), and Sheffield (2021). , Oxford is claiming to become the first city to implement a Zero Emission Zone (ZEZ) scheme, beginning with a small area to go into effect by mid 2021. It was postponed from a 2020 start due to the economic impacts of the COVID-19 pandemic. However, the proposals can more accurately be described as a Low Emission Zone or Ultra Low Emission Zone as any vehicle can enter on payment of a charge.