Six-month review highlights air quality benefits of London’s expanded ULEZ

A report from London’s City Hall assessing the impact of the first six months following expansion of the Ultra Low Emission Zone (ULEZ) has found that the both the number of older, more polluting vehicles driving in central and inner London and the levels of harmful pollution have fallen substantially.

In October 2021 Mayor of London, Sadiq Khan expanded the ULEZ to cover all areas inside the North and South Circular roads, 18 times the size of the original zone.

The report shows that 94 per cent of vehicles seen driving in the zone now meet the strict ULEZ standards on an average day, up from 87 per cent in the weeks before the zone expanded and up from 39 per cent in February 2017 when changes associated with the ULEZ began.

There were also 67,000 fewer non-compliant vehicles in the zone on an average day compared to the period right before the ULEZ expanded, a fall of 54 per cent. Early estimates suggest the number of vehicles overall in the zone has also fallen by around 21,000. ULEZ has also helped prevent a return to previous pollution levels after the pandemic, even as traffic returned to close to 2019 levels.

These factors, says the Mayor, mean that the four million Londoners living within the expanded ULEZ are now breathing cleaner air than they would have without the scheme. NO2 concentrations in inner London are estimated to be 20 per cent lower than they would have been without the ULEZ and its expansion. In central London, NO2 concentrations are estimated to be 44 per cent lower.   

The report comes as Sadiq, in his twin roles as Mayor of London and Chair of C40 Cities, convenes a meeting of representatives from 16 global cities, health experts, youth activists and union leaders at City Hall.

Mayor of London, Sadiq Khan said, “I’m proud of the progress we have made in making our city’s air cleaner for millions of Londoners. The report shows the incredible difference that the expanded ULEZ is making after just six months. We must now capitalise on this success which is why I’m consulting on expanding the ULEZ London-wide to extend the benefits of clean air to all Londoners.

"We have already come so far and I’m determined to build a better London for everyone, one that is safer, fairer, greener and more prosperous for all. But we cannot act alone. As Chair of C40 Cities, I am committed to working collaboratively across national borders and city boundaries to tackle air pollution, address the climate crisis, and help bring about the change we need to achieve the UN’s Global Goals for sustainable development.”

Mark Watts, Executive Director, C40 Cities added, “Air pollution is a deadly problem in cities across the world. Road transport is the single largest source of toxic air pollution in London, leading to severe respiratory issues and devastating premature deaths.

“This report shows the real difference bold ambitious plans can make. What London is doing will be keenly watched across the world, inspiring many other mayors to invest in cleaner, greener, and fairer cities.”

However, the report also shows that there is still more work to do to ensure all Londoners can experience the benefits of cleaner air. Compliance rates and air quality improvements in outer London – which is not currently covered by the ULEZ – continue to lag well behind those in central and inner London. This is why the Mayor has asked TfL to consult on expanding the ULEZ London-wide in August 2023.