Clean air zones (CAZs) have become a critical method of transport emissions management in the UK, part of a shift in the country's wider air quality strategy.
Understanding how requirements and charges differ across CAZs is essential for businesses running vehicle fleets, so they remain compliant while adapting to growing pressure to reduce supply chain emissions.
Ahead of the 2026 Air Quality & Emissions Expo (AQE), we explain how CAZs operate, how they differ from other schemes such as Low Emission Zones (LEZs), and what businesses should expect from UK air quality policy in the coming years.
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What Are Clean Air Zones (CAZs) and How Do They Work?
A CAZ is a designated area where local authorities take targeted measures to improve air quality. Each CAZ sets its emissions standards and rules, and vehicles must meet these standards to enter without restrictions. Those that don't meet the requirements must pay a charge to enter.
CAZs are classified into one of four classes depending on which vehicles face restrictions:
- Class A: Restrictions on buses, coaches, taxis and private hire vehicles
- Class B: Restrictions on Class A vehicles plus heavy goods vehicles (HGVs)
- Class C: Restrictions on Class B vehicles plus vans and minibuses
- Class D: Restrictions on Class C vehicles plus private cars
Local authorities decide the class of a CAZ based on the air quality challenges of that region. Charges, exemptions and enforcement arrangements also vary.
The government offers an online resource that lets you check whether a vehicle meets the emissions standards of a CAZ before you enter.
Where Are the Major CAZs Operating in 2026?
England has seven CAZs, all of which operate under the same legislative framework. Currently, no Class A CAZ is in operation.
|
City |
CAZ Class |
Area covered |
Vehicles charged |
Typical daily charge* |
|
Bath |
Class C |
Bath City Centre |
Taxis, private hire vehicles, vans, minibuses, HGVs, buses and coaches |
|
|
Birmingham |
Class D |
Areas inside the A4540 Middleway Ring Road |
Cars, taxis, vans, HGVs, buses and coaches |
|
|
Bradford |
Class C |
Bradford City Centre and surrounding routes |
Taxis, vans, minibuses, HGVs, buses and coaches |
|
|
Bristol |
Class D |
Central Bristol |
Cars, taxis, vans, HGVs, buses and coaches |
|
|
Portsmouth |
Class B |
South-west Portsmouth |
Buses, coaches, taxis, private hire vehicles and HGVs |
|
|
Sheffield |
Class C |
Sheffield Inner Ring Road and City Centre |
Taxis, vans, minibuses, HGVs, buses and coaches |
|
|
Tyneside (Newcastle and Gateshead) |
Class C |
Newcastle City Centre and key river crossings |
Taxis, vans, HGVs, buses and coaches |
|
|
York |
Bus-only (Class A equivalent) |
Much of Central York |
No daily access charge, but local buses entering the zone five or more times per day must either be electric or meet Euro VI emissions standards. |
|
Beyond the CAZ Framework: London, Scotland and Other Emission Models
Not every UK city follows the CAZ model. Authorities have adopted different approaches based on local transport priorities, legal frameworks and air quality challenges.
These differences have created distinct charging models across the UK — from London's Ultra Low Emission Zone (ULEZ) to Scotland's LEZs and Oxford's Zero Emission Zone (ZEZ).
London's ULEZ
The ULEZ is stricter and wider in scope than the CAZ. Rather than targeting specific vehicle classes, it restricts all vehicles that don't meet its emissions standards, including:
- Motorcycles, mopeds, motorised tricycles and quadricycles (these are subject to Euro 3 standards)
- Petrol vehicles, including cars, vans and minibuses (subject to Euro 4 standards)
- Diesel vehicles, including cars, vans and minibuses (subject to Euro 6 standards)
Non-compliant vehicles must pay a daily charge of £12.50. Separate charges may also apply under other schemes, like the London Congestion Charge and LEZ.
Launched in 2019, the ULEZ originally covered only Central London, but was expanded to all London boroughs in August 2023.
Scotland's LEZs
Scotland operates LEZs in Aberdeen, Dundee, Edinburgh and Glasgow. Unlike English CAZs, which allow non-compliant vehicles to enter if they pay a charge, Scottish LEZs don't let them enter at all unless an exemption applies.
Drivers who enter an LEZ in a non-compliant vehicle must pay a penalty of £60, reduced to £30 if they pay it within 14 days. Further breaches by the same vehicle within 90 days trigger progressively higher penalties: up to £480 for cars and light goods vehicles and £960 for buses, coaches and HGVs.
By removing the option of paying to enter in a non-compliant vehicle, Scotland's approach encourages long-term compliance through vehicle replacement, retrofitting or changes to travel behaviour. This is in line with Scotland's wider strategy to improve air quality, protect public health and promote sustainable transport.
Oxford and York's alternative approaches
Oxford and York have adopted more targeted approaches than CAZs, focusing on specific local air quality priorities rather than introducing broad charging schemes.
Oxford's ZEZ
Oxford launched the UK's first Zero Emission Zone (ZEZ) pilot in the city centre. Unlike CAZs, which charge certain classes of vehicles, the ZEZ charges all petrol, diesel and hybrid vehicles, with the rate varying based on a vehicle's emissions. Zero-emission vehicles, such as electric vehicles, can enter without paying a charge. Oxford is using the pilot to assess how a central charging model can support a wider, longer-term move towards zero-emissions transport throughout the city.
York's bus-focused CAZ
York has taken a different approach. Rather than introducing charges for multiple vehicle types, its Class A CAZ focuses solely on local bus services. The scheme doesn't impose charges on private cars, vans or HGVs. Still, it requires local bus operators to upgrade fleets to cleaner or zero-emission vehicles to reduce nitrogen dioxide concentrations in the city centre.
Wales and Northern Ireland's Local Quality Air Management framework
Wales and Northern Ireland address air pollution through the Local Quality Air Management (LAQM) framework, among other legislation. LAQM empowers local authorities, like district councils, to monitor regional pollutants and introduce targeted measures.
If air quality objectives in a certain area aren't expected to be met by the target deadline, the local authority must designate it as an Air Quality Management Area (AQMA) and write a custom action plan to bring it back on track.
Wales has also implemented the Environment (Air Quality and Soundscapes) (Wales) Act, which targets a reduction in noise pollution to meet wider air quality goals.
What CAZs Mean for Businesses
For businesses, the impact of CAZs goes beyond daily charges. These schemes influence how they plan routes, manage fleets, control operating costs and meet environmental obligations.
Access and logistics
Businesses operating nationally must navigate different charging schemes, vehicle standards and exemptions depending on where they operate. A vehicle that complies in one city may incur charges in another, making route planning more complex.
Many organisations now use telematics, route optimisation tools and fleet management software to identify compliant routes and minimise unnecessary charges.
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Higher operational costs
Daily CAZ and ULEZ charges can significantly increase operating costs for businesses running older vehicles. Companies making frequent deliveries into city centres often face the greatest financial impact.
Businesses are comparing the long-term cost of paying daily charges with the investment needed to upgrade vehicles or replace ageing fleets. For high-mileage urban fleets, replacement may prove more cost-effective, while businesses with occasional exposure may consider continuing to pay daily charges in the short term.
New compliance responsibilities
To comply with varying requirements under different schemes, fleet managers must:
- Maintain accurate vehicle records
- Check emissions standards before journeys
- Track charges, exemptions and payment deadlines
Businesses that use contractors or leased vehicles also need clear processes for confirming compliance, allocating charges and avoiding penalties. For companies with larger fleets, these checks increasingly form part of procurement, journey planning and supplier management.
Accelerated fleet investment
CAZs have encouraged many businesses to modernise vehicle fleets. Organisations are investing in environmentally friendly vehicles — electric, alternatively fuelled or Euro 6 — based on where they operate.
By helping them cut fuel use and tailpipe emissions, this shift is setting up organisations to meet future air quality standards: Under the UK's zero-emission vehicle mandate, sales of new petrol and diesel cars will be banned after 2030, while all new cars and vans must be zero-emission by 2035.
Understanding Industrial Emissions Policy
In contrast to CAZs, which target emissions from vehicles, industrial emissions policy deals with pollution from fixed installations such as factories, power stations, waste treatment sites and manufacturing plants.
What counts as industrial emissions?
Fixed installations release industrial emissions like nitrogen oxides, sulphur dioxide, particulate matter (PM2.5 and PM10) and volatile organic compounds, depending on the process and fuel used. These emissions contribute to the UK's overall pollution burden alongside transport, agriculture and construction.
The contribution of each sector varies by pollutant: In 2024, road transport accounted for 30% of the UK's nitrogen oxide emissions, while the combustion of fuel in energy industries accounted for 20%. But industrial combustion also contributed 10% of the UK's PM2.5 emissions and 6% of PM10 emissions in the same year.
These emissions matter because exposure to particulate matter can damage lung function and increase the risk of respiratory disease, heart disease, stroke and cancer. Nitrogen dioxide can irritate airways and aggravate asthma and other respiratory conditions.
Effectively, industrial emissions policy works alongside CAZs to improve the UK's national air quality levels.
How industrial emissions are regulated
Regulators manage industrial emissions through permits, monitoring and Best Available Techniques (BAT).
The Environmental Permitting (England and Wales) Regulations 2016 require operators to obtain permits for the industrial activity they manage. Different industries, including energy generation and waste management to food production, chemicals and heavy manufacturing, are subject to different requirements. Either the Environment Agency or local authorities issue permits, depending on the activity.
In general, operators must:
- Comply with emissions limits and operating requirements of their permit.
- Monitor and report emissions at the frequency specified in the permit.
- Apply BAT to prevent or minimise emissions.
- Follow decisions of inspections and permit reviews, including upgrading equipment or updating charge budgets where standards are no longer met.
If a business breaches the conditions of its permit, regulators can suspend operations, revoke its permit, impose civil sanctions or prosecute it legally. The action taken depends on the seriousness of the breach, the environmental harm caused and the operator's compliance history.
What's Next for Air Quality Policy?
Several policy developments will continue to shape the UK's air quality framework over the coming years.
Strengthening air quality targets
The Environment Act framework requires England to reduce average PM2.5 concentrations to 10μg/m³ or below by 2040 and cut population exposure by at least 35% from 2018 levels. An interim target requires a 22% reduction by January 2028.
Local authority action
Local authorities will continue reviewing existing CAZs and wider air quality plans against changing pollution levels. Where objectives aren’t met, councils may adjust zone boundaries, exemptions and enforcement arrangements or introduce targeted measures through regional frameworks.
Industrial decarbonisation
The UK will progressively implement industrial decarbonisation policies, including carbon pricing under the UK Emissions Trading Scheme and carbon capture projects. These policies form part of the wider effort to reduce industrial emissions while developing the infrastructure and regulatory framework needed for lower-carbon production.
Greater integration with climate policy
The UK government continues to align air quality and climate policy measures through cleaner transport, industrial decarbonisation and reduced greenhouse gas emissions. Consequently, air quality objectives are increasingly complementing wider net-zero policies rather than operating as separate environmental priorities.
"The main issues for industrial emissions regulation relate to the tighter emission standards, and the new emissions monitoring requirements from new sources, such as Carbon Capture plant[s] and extensions of the UK emissions trading scheme," says Rod Robinson, principal scientist at the National Physical Laboratory (NPL) and a speaker at AQE 2026. "The changing face of emission sources, for example, with smaller local power generation and load balancing, biogas, anaerobic digesters and agricultural sources, is also leading to new measurement requirements."
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What Businesses Can Do Now
Businesses shouldn't wait for new legislation to take action. A practical compliance plan can reduce costs and penalties and support longer-term fleet and investment decisions. Some strategies to consider include:
- Audit fleet compliance: Check which vehicles — including leased, hired and contractor-operated ones — meet CAZ and ULEZ standards. Keep records of exemptions, payment responsibilities and renewal dates.
- Track local scheme changes: Assign responsibility to specific personnel for monitoring updates to zone boundaries, charges, exemptions and enforcement rules in each area where the business operates.
- Draft fleet replacement plans: Identify vehicles that regularly enter regulated areas and compare the cost of daily charges with newer Euro 6 models or electrification.
- Upgrade journey planning: Use telematics and route planning tools when allocating vehicles to increase mileage and reduce charges.
- Review industrial permits: Confirm that internal practices remain up to date with monitoring, reporting and BAT requirements.
- Address supply chain emissions: Work with transport providers, subcontractors and suppliers to identify opportunities to reduce emissions across the supply chain.
What's Coming Next: The Air Quality Policy Landscape Through 2027
As air quality policy evolves, the spotlight is turning from introducing charging schemes towards improving how emissions are monitored, measured and managed.
For instance, there are "increasing demands for reporting methane and other [greenhouse gas] GHG emissions, including from diffuse and fugitive sources," Robinson says." These new monitoring requirements will need new methods to be developed and validated to provide the assurance in data reported by industry."
Several themes will shape discussions among government, industry and academia through 2027:
- Smarter air quality monitoring: Low-cost sensors, connected monitoring networks and real-time data are making it easier to measure pollution and assess the effectiveness of air quality policies.
- Industrial emissions measurement: Regulators and operators continue improving emissions monitoring, reporting and verification to support environmental permitting and industrial decarbonisation.
- Non-exhaust emissions: Attention is turning to particulate matter emissions from tyres, brakes and road wear, which remain a major source of urban air pollution.
- Digital technologies and AI: Environmental professionals are exploring AI, predictive modelling and digital twins — virtual replicas of physical objects and systems — to improve pollution forecasting and environmental decision-making.
- Learning from existing schemes: Local authorities, regulators and researchers are evaluating the impacts of CAZs, ULEZ and LEZs to understand their effectiveness and inform future air quality policy.
These topics are expected to feature prominently at the Air Quality & Emissions (AQE) Show, part of the Environmental Services & Solutions Expo (ESS). The event will bring together regulators, policymakers, technology providers and industry leaders to discuss the latest policy, technology and compliance developments shaping air quality in the UK.
For businesses, keeping pace with these developments will be just as important as understanding today's regulatory requirements.
Register for the 2026 AQE Expo today.
FAQs: UK Clean Air Zones
Which UK cities have Clean Air Zones (CAZs)?
CAZs currently operate in Bath, Birmingham, Bradford, Bristol, Portsmouth, Sheffield and Tyneside (Newcastle and Gateshead). Each city sets its own charging rules, vehicle classes and exemptions.
What is the difference between a Clean Air Zone (CAZ) and ULEZ?
CAZs are introduced by local authorities under England's national CAZ framework and may charge different vehicle classes depending on regional air quality standards and targets. London's ULEZ operates under separate legislation and applies emissions standards to almost all vehicles, including private cars.
How can businesses avoid CAZ charges?
Businesses can reduce or avoid CAZ charges by operating compliant vehicles, planning routes carefully, monitoring local scheme requirements and upgrading older fleet vehicles.
Author Bio: Angeliki Tsolka is a sustainability professional with more than 13 years of international experience across the UK, Europe, and the Middle East. She has worked on major infrastructure, energy, industrial, and urban regeneration projects, supporting clients through sustainability-focused assessments, reporting, and regulatory compliance. With a strong technical background and previous experience as a Waste Management Consultant in the UK, she brings both practical industry knowledge and strategic sustainability expertise to her work.
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