Coming up for air
The road ahead for pollution in London
Written by Chris Fellingham for the Greater London Project. You can read Chris’ own Substack here.
“London’s air quality is now on track to meet UK legal limits by next year – 184 years earlier than previously projected. Despite this progress, air pollution levels in London will continue to exceed WHO clean air guidelines in 2025 and 2030.” - Mayor of London
London has a long history of fighting air pollution, from its nickname ‘the big smoke’ in the Victorian era to its ‘pea soup’ and ‘Great smog’ in the 1950s. These challenges have been with legislation and policy designed to improve public health – the Clean Air Acts of 1952 and 1968 reduced industrial emissions, switched home heating to cleaner options like gas, and large sources of pollution like power stations were moved away from population centres.
In the 21st century, London’s air pollution problems stem primarily from transport emissions. Internal combustion engines and tyre abrasion create a combination of toxic gases such as Nitrogen Oxide, particulate matter, and volatile non-organic compounds (VONC) which end up in our lungs. The toll on public health is significant, with air pollution causing approximately 9,400 premature deaths per year, cardiovascular conditions like asthma, as well as stunted lungs and early childhood obesity. London made a grim first in legal history when Ella Kissi-Debrah was the first person in the UK to have air pollution listed as a cause of death.
Despite the scale of the challenge, London had been making progress. The Ultra Low Emission Zone (ULEZ) introduced in 2016, has been the main tool for tackling air pollution, and a successful one at that. ULEZ charges vehicles whose engines are below a certain euro standard. The European emission standards categorise vehicles across seven levels, and set emission thresholds for pollutants. By charging vehicles whose engines fall below specific thresholds, ULEZ has pushed older, more polluting cars off the road. Since its introduction, air pollution concentrations have fallen by 65% in the very centre of London, by 53% in inner London, and by 45% in outer London.
While ULEZ has been highly successful, it should be a stepping stone on the way to further reforms. One option would be to raise the engine standards required to avoid paying the ULEZ charge even higher, but this whilst this would reduce exhaust emissions it would do nothing to tackle the increasingly well-evidenced pollution caused by tyre-wear.
In fact, an even bolder plan is in play. Courtesy of some brilliant reporting by Jim Waterson in London-centric, we now know the Mayor’s plan was to replace ULEZ with a much more ambitious plan to introduce road-user charging in London. The plan would’ve seen anyone driving in the capital charged per mile, with rates varying depending on whether they were driving in inner or outer London. TfL’s modelling suggests it would have resulted in 600,000 fewer car journeys.
Unfortunately, this cleaner air future has been cancelled. In the run up to his third term, London Mayor Sadiq Khan ruled out both further changes to ULEZ and road-user charging – likely caused by the bruising Uxbridge by-election in 2023 where ULEZ expansion was clearly a decisive issue in the Conservative victory.
With no further changes planned to ULEZ and the road-user charging scrapped, what next for London’s pollution policy?
The road ahead
In lieu of a major policy change such as ULEZ or road-user charging, the Mayor’s office will focus on a plethora of smaller policies to bring emissions down across the capital. In practice these take two forms, reducing journeys taken by private vehicles, or electrifying transport which eliminates exhaust emissions.
The Mayor’s office continues to promote public transport, active travel and pedestrianisation, all of which will help reduce private travel in polluting vehicles. This includes segregated cycle lanes and cycleways (which route cyclists through quiet backstreets), junction redesign (to improve cycling safety) such as Holborn junction and Lambeth Bridge. The most eye-catching is the Mayor’s proposal for pedestrianisation of Oxford Street (although unfortunately Soho will not be included).
London is a leader in electric vehicle adoption, both in private vehicles (where London leads the UK) and in public transport. The Mayor’s office and the councils have supported EV transition, sometimes through direct funding rollout of electric charging as well as supporting electric and cargo delivery networks.
When it comes to electrifying public transport, TfL currently has plans to green the fleet by 2030 (funding permitting). Currently 17% (about 1,500 of 8,776 strong fleet) of TfL’s buses don’t generate emissions, and an additional £500 million is being spent to purchase another 1,000 by 2026. Given buses account for ~13% of all journeys in the capital, this should have a significant impact on air pollution.
There are bolder steps the Mayor could still take. One option would be to increase the congestion charge – a fixed charge of £15 for anyone driving into central London during peak hours. As of 2025, EV users will be charged the same as any other vehicle (an example of how the mix of policies can sometimes work against each other – in this case pitting congestion against electric vehicle adoption). The Mayor could instead further increase the price for non-EV drivers, discouraging congestion or encouraging drivers to switch to electric vehicles.
Bolder still would be to double down on repurposing London’s spaces. TfL is responsible for over 6,712 parking spaces (excluding accessibility spaces). The Centre for Cities have proposed repurposing spaces away from car use in favour of outdoor seating for shops, bars and restaurants, active travel (bike stands), or green spaces. And evidence from Amsterdam shows reducing parking spaces in a city centre nudges people to use public or active travel options instead. If the Mayor wanted to be really bold, he should request control of further arterial routes to ensure active travel options are not blocked and deepen pedestrianisation in the centre.
Exciting as these ideas seem to be, unless the primary tools to reduce pollution (ULEZ and road-user charging), air pollution will be hard to reduce further. Instead, Londoners will be reliant on piecemeal policies that vary by borough, and at times conflict with other goals such as reducing congestion. The capital’s air and the health of its citizens will improve, but slowly and unevenly.
Community notes:
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