London mayor points to improving air quality but critics say it remains a “cash grab” on motorists, reports Kumail Jaffer, Local Democracy Reporter
Sadiq Khan and (inset) Ulez
Mayor of London Sir Sadiq Khan has hailed his controversial Ultra Low Emission Zone (Ulez) policy as “bold” and “transformative” two years after its expansion to the outer boroughs.
Ulez, first introduced in 2019, has been expanded twice – once in 2021 to cover anything inside the North Circular and South Circular roads, and again in August 2023 to cover all 32 London boroughs.
Last week marked the two-year anniversary of the full rollout, which sparked anger, legal challenge and a lot of debate on social media at the time – but Khan subsequently won a landmark third term in 2024 despite his top opponent Susan Hall strongly opposing Ulez.
The London-wide zone measures 1,500 square kilometres and covers nine million people, making it the largest of its kind in the world. The intention is to improve London’s air quality by discouraging the most polluting vehicles from being on the roads.
To do this, drivers of older cars which fail to meet emission standards are compelled to pay a £12.50 fee for every day they drive in any of London’s boroughs. This applies largely to pre-2005 petrol vehicles and pre-2015 diesel models.
Both the introduction and expansion of Ulez were seen as an unfair tax on motorists by critics.
Two years on, however, it’s clear that the clean air zone has played some part in clearing up London’s smog.
Figures from City Hall have revealed that NOx emissions, which can cause inflammation of the airways and increase susceptibility to respiratory infections and to allergens, were estimated to be 36% in 2024 than they would have been had Ulez not been introduced.
This figure was 14% in outer London. The region also saw an 82% reduction in people exposed to illegal levels of pollution.
Similarly, concentrations of NO2, or nitrogen dioxide, were estimated to be 54% lower in central London, and 27% lower across the whole of the capital.
Cumulatively, carbon emissions are estimated to be 813,000 tonnes lower due to Ulez – the equivalent of nearly three million passenger trips between Heathrow and New York.
Khan said: “Ulez is the world’s largest clean air zone, and thanks to this bold policy and our other transformative air quality policies, all Londoners and visitors are now breathing cleaner air while thousands of polluting cars have been taken off our roads meaning levels of toxic air pollution have substantially decreased.
“Two years since Ulez expanded London-wide, I’m proud the evidence shows it’s been even more effective than expected in helping to improve the health of Londoners, support children’s lung growth and ultimately save lives.
“Due to these pioneering policies, we are close to bringing air pollution within legal limits and I remain committed to improving air quality across the capital as we continue building a greener, fairer, better London for everyone.”
The introduction of the scheme was criticised for leaving some poorer Londoners facing a £12.50 daily charge if they could not afford a newer vehicle, or stopping using their car altogether.
However, a scrappage scheme, which originally offered up to £7,000 compensation if a polluting car was handed over, paid out £186million for more than 53,000 older vehicles to help motorists. Of these units, 684 were donated to support medical and humanitarian efforts in Ukraine.
The results have prompted calls for the mayor to go even further in his battle to clean up London’s air.
Caroline Russell, Green Party London Assembly member, told the Local Democracy Reporting Service: “London’s air is 27% cleaner thanks to the Ulez – proof that bold action works.
“The success of the Ulez is testimony to the many campaigners who pushed and pushed for the mayor to act, so that Londoners can trust the air they breathe. But the work is far from over. Congestion is still a huge issue and more needs to be done to give people the confidence to ditch their cars for good.”
The introduction of Ulez was far from smooth, however.
As well as his political opponents, the London mayor has faced resistance from councils in London – four of whom launched a High Court challenge to the August 2023 expansion – and even his Labour Party colleagues.
MPs Seema Malhotra, Jon Cruddas, Siobhain McDonagh and Abena Oppong-Asare all came out publicly against the outer London expansion.
A month prior to the move, Labour lost a high-profile by-election in Uxbridge and South Ruislip, prompting leader Sir Keir Starmer to urge Khan to “reflect” on its rollout.
Ulez infrastructure itself has also fallen victim to organised vandalism. So-called ‘blade runners’ said they intended to destroy all cameras tasked with enforcing the scheme.
The mayor has refused to budge on his support for Ulez, saying in March that he has “no plans to move the goalposts” when it comes to vehicle standards. That same month, figures revealed that over 97% of vehicles seen driving in London were Ulez-compliant.
But he is likely to face continued opposition from both the Tories and Reform UK in an attempt to tap into the anger that remains among some in the city’s outer boroughs.
Keith Prince, the City Hall Conservatives transport spokesman, told the LDRS: “Two years on, Sadiq Khan’s outer London Ulez has slapped drivers with over two million fines and £224m from their pockets, yet pollution levels have barely shifted. This is nothing more than a cash grab to mask his wider failures at City Hall.”
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