City of York Council: York’s Clean Air Zone

City of York Council took action to improve air quality across the city through a Clean Air Zone, aiming to significantly reduce emissions from buses and ensure all those operating frequently in the city centre were low emission.

The challenge

Buses have had a disproportionate impact on air pollution in York city centre. Reducing their emissions would have the greatest impact on both air pollution and carbon emissions.

The solution

City of York Council declared three Air Quality Management Areas (AQMAs) where air pollution exceeded health-based targets, requiring action to be taken. Their transport policy at the time focused on sustainable travel – walking, cycling and public transport – but it was found that older diesel buses were a disproportionate contributor to poor air quality in the city centre and elsewhere in York.

The Council's Air Quality team came up with the idea for the UK’s first holistic Low Emission Strategy in 2012 to ensure both air pollution and carbon emissions were reduced at the same time. This led to a series of measures in their third air quality action plan, the most important of which was a bus-based Clean Air Zone (CAZ) in York city centre. The plan was to phase out older diesel buses in favour of ultra-low emission buses that were either fully electric or fuelled by Euro 6 diesel.

Rather than use expensive cameras, a Traffic Regulation Order was agreed by the Traffic Commissioner banning older diesels from the city centre. Since most buses had a city centre destination, this move also saw a reduction in emissions across the whole of York.

The Council have 33 electric buses, 21 of which are new double deckers, which are currently serving park and ride routes, as well as others.


The project was conceived by the public protection (air quality) team, with support from transport colleagues and others. Reservations from the bus industry were overcome by working together.

The team applied for council funding alongside grants from the Department for Environment, Food and Rural Affairs (DEFRA) and the Department for Transport (DfT) to assist with the purchasing of new electric buses and the retrofitting of older diesel models. City of York Council gave £1.65m to five bus operators to help replace/retrofit 93 buses to CAZ compliant standards. £240k of this was from air quality grant which went towards retrofitting 12 buses; match funding of approximately £120k was offered by operators as part of the bid to retrofit additional vehicles. £3.3m from DfT’s Low Emission Bus Scheme was used to support the delivery of fully electric buses and charging infrastructure at York’s Park and Ride sites.

The proposals went through extensive consultations and received overwhelming public support.

The impact

Over the course of the project all of the Air Quality Management Areas, bar the city centre, have seen such significant improvements in their air quality that they no longer qualify to be part of the scheme. York has now met its air quality target for all pollutants.

As well as the buses being better for air quality – clean, reliable, and modern – they are also Wi-Fi enabled, meaning that visitors and residents have access to public transport fit for 21st century life. The environmental improvements will also go towards improving the health of the people of York.

Since York is a small, compact and very flat city, it’s ideal for electric transport. Similar cities could see the benefits they have made.

All buses that serve the city centre CAZ five or more times a day must either be electric or diesel Euro VI. As such, of all of the buses operating across York it is estimated that 90-95 per cent are electric or Euro VI.

How is the new approach being sustained?

The project has now been completed. All regular city centre buses are now electric or run on Euro 6 diesel. The CAZ was fully in place by 31 January 2021 after a 12 month “sunset” period which allowed suppliers to complete orders.

Lessons learned

Over the course of this project, certain key factors were identified as being crucial to its success, and which would be useful to other councils looking to overhaul their public transport offerings. These were:

  • setting a clear timetable for phasing out older diesels
  • meeting with bus operators to discuss their many concerns
  • securing funding within the Council and from Government departments.

Another important element was the fact that the CAZ project proposal was part of a wider Air Quality Action Plan and Low Emission Strategy which was designed to help reduce emissions from all sources in the area.

As outlined above, CAZ works as part of a wider Air Quality Action Plan. Air quality improvements are being monitored by York’s extensive air quality monitoring network, which includes nine real time air quality monitoring stations backed by nitrogen dioxide diffusion tubes installed in over 230 locations in the city.

The plan has:

  • set emission standards for taxis and encouraged a transition towards ULEVs, backed up by a Low Emission Taxi Grant that provides funding of up to £3,000 to purchase lower emitting taxi cars, leading to a quarter of York’s taxis being fully electric or petrol hybrids
  • increased the number of ULEVs within the Council’s own fleet
  • expanded the EV recharging network
  • raised public awareness of the impact of pollution on health
  • improved how we tackle idling from buses and other vehicles
  • investigated the reduction in emissions from delivery vehicles.

Electric buses that now operate on most of the major routes have zero tailpipe emissions.


Mike Southcombe, Public Protection Manager, City of York Council, [email protected]