Ditch Diesel
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Our diesel campaign calls for:
Commitments from all levels of government to phase out diesel by 2030
A manufacturer recall of all diesel cars that are found to have defeat devices installed
A major UK fund, put together by car manufacturers, worth at least £1 billion to support the phasing out of diesel
Health effects of air pollution from diesel
Exposure to air pollutants can shorten life expectancy and is linked to various negative health effects. Children are developing lifelong, chronic conditions, including poorly developed lungs, asthma, high blood pressure, inattention and hyperactivity, and mental illness as a result of exposure to air pollution.
Diesel vehicles emit nitrogen oxides (NOx) and nitrogen dioxide (NO2), gases which inflame lungs and are closely linked to childhood asthma and wheezing.
The short-term effects of exposure to NO2 include inflammation of the lungs and airways, and long-term exposure can affect lung function and breathing and worsen asthma.
How much air pollution do diesel vehicles create?
On average in the UK in 2023, 68 per cent of the NO2 concentrations at the roadside were estimated to have originated as NOx emissions from road transport, and diesel vehicles are the single biggest contributor to the NOx on our roads, as shown here in this graphic from Professor Chris Whitty’s Air Pollution Report (Figure 6, Page 8).
In March 2025 Mums for Lungs commissioned research that revealed that 7.5 million of the UK's 10.7 million diesel cars are Euro 5 and 6 models, emitting 51,400 tonnes of excess NOx annually above legal emission limits (as of June 2024). Diesel cars certified to Euro 5-6 standards were shown to be using defeat devices which cheat emissions tests during the Dieselgate scandal.
This is why we urgently need national and local government to phase out diesel.
Dieselgate and real-world diesel emissions
The 2015 Dieselgate scandal revealed that defeat devices were allegedly fitted to diesel vehicles to artificially reduce emissions to pass EU tests. Government agencies across Europe subsequently began to test real-world emissions and discovered that diesel cars across manufacturers emit higher levels of NOx during real-world operation than in laboratory testing.
The International Council on Clean Transportation’s 2017 white paper revealed that some Euro 6 diesel cars (those that are allowed within London’s Ultra Low Emission Zone) were found to exceed the legal limit of 80 mg/km NOx by a factor of 12. The Real Urban Emissions (TRUE) Initiative has given nearly all diesel vehicles on European roads a “poor” rating.
A subseqent 2023 reassessment of excess NOx in diesel cars in Europe revealed that “suspicious” levels of NOx emissions were found in 77 per cent to 100 per cent of tests and vehicle averages, indicating the likely use of a prohibited defeat device. This led environmental law charity Client Earth to send a legal complaint to the UK Government, demanding they address the legacy of Dieselgate.
The legacy of Dieselgate - 2025 class action
In 2024 the Department for Transport began investigating prohibited defeat devices in diesel vehicle models. Several law firms launched the biggest group claim ever to come before any of the UK courts, representing more than 1.5 million vehicle owners. The details of the case have been deemed confidential due to the commercial interests of the defendants, the car manufacturers. We believe there should be full transparency about the vehicle emissions we are all breathing.
Mums for Lungs has written an open letter to the judge in the case, calling for documents related to the litigation to be made publicly available due to the significant public interest in this matter. The letter has been signed by over 650 individuals, MPs and over 50 charities and campaign groups.
We are calling for all affected cars to be immediately recalled by the manufacturers, and for a major UK fund worth at least £1 billion to be put together, in order to pay for measures to alleviate the impact of the air pollution car manufacturers are responsible for.
Taking action - how to phase out diesel vehicles
National government can bring forward the end of the sale of new petrol and diesel internal combustion-engined (ICE) cars in the UK to 2030, and provide incentives to encourage the purchase of electric vehicles.
Local authorities can fast-track the phase-out of diesel vehicles by:
• Phasing out new residential parking permits for diesel cars
• Introducing emissions-based parking tariffs
• Creating zero-emission loading bays and taxi ranks
• Setting a vision and publicly committing to a diesel-free borough by 2030
We know that it will take longer to transition away from diesel vans, which is why the 2030 deadline needs to be set now. The UK Government needs to support industry to bring cleaner alternatives to market – current offerings are limited and expensive.