New data shows Mayor’s action is dramatically cleaning up London’s air

20 February 2020
  • Almost 100 per cent reduction in illegal peaks in pollution since Sadiq became Mayor

  • Mayor’s Flagship Low Emission Bus Zone schemes has cut harmful NO2 pollution 

New data released today shows that air quality in some of London’s worst pollution hotspots has significantly improved since 2016 when Sadiq Khan began to implement policies to clean up London’s toxic air.

The figures reveal that during 2016, London’s air exceeded the hourly legal limit for nitrogen dioxide for over 4,000 hours. Last year, this fell to just over 100 hours – a reduction of 97 per cent. Between 2004 to 2017 London breached the permitted number of exceedances for NO2* within the first week of the year. In 2019 only one site breached and it did not occur until July.

There have also been significant reductions in Londoner’s long-term exposure to air pollution, with every monitoring site in the capital recording a reduction in annual average NO2 levels. Londonwide, there has been an average reduction of 21 per cent between 2016 and 2019.

Nitrogen dioxide is a toxic gas which aggravates respiratory diseases - particularly asthma – and stunts the development of children’s lungs. Significant NO2 reductions have occurred where Sadiq has introduced Low Emission Bus Zones – areas where only buses that meet the cleanest emission standards can operate:

  • At Putney High Street in Wandsworth, NO2 levels have stayed within legal limits so far this year, compared to 1,279 hours of illegal levels in 2016.
  • At Brixton Road in Lambeth NO2 levels remained within legal limits for the entirety of 2019 and so far this year, compared to 530 hours above the legal limit in 2016. In 2017, this site saw London’s first breach of annual pollution limits just five days into the new year, and in 2018 it occurred within a month.
  • On Oxford Street in Westminster, NO2 exceeded legal limits for 168 hours in 2016. In 2019 monitors did not record a single hour above legal limits. However, there is also an annual average legal limit which Oxford Street did not meet, which is why further action is needed.


The Mayor of London, Sadiq Khan, said: “Toxic air is a national health crisis contributing to thousands of premature deaths ever year. I have taken bold action in London with measures such as the world’s first Ultra Low Emission Zone and Low Emission Bus Zones, and it’s undeniable that these are making a difference to the air we breathe.


“We’re doing all we can in the capital, with proven results, so there are no excuses left for the Government’s failure to match our levels of ambition.”


Since he became Mayor, Sadiq has:


  • Planted more than 280,000 trees, more than the previous Mayor planted in 8 years.
  • Pledged to make the capital carbon neutral by 2030, 20 years earlier than the Government’s target.
  • Introduced the world's first Ultra Low Emission Zone in 2019, resulting in 13,500 fewer polluting vehicles driving in the zone every day and toxic NO2 levels falling by a third in the zone.
  • Delivered 12 Low Emission Bus Zones ahead of schedule, cutting bus-related NOx emissions by an average of 90 per cent in the zone.
  • Worked with schools in some of the most polluted areas of London to reduce children's exposure to air pollution.
  • Installed 1,500 charging points across the capital, with more than 1,000 new electric vehicle charging points to be installed in residential areas next year.
  • Transformed London's taxi fleet by no longer licensing new diesel taxis. There are now over 3,000 electric taxis on London’s streets.
  • Set up a £48m scrappage fund available to help small businesses, low-income and disabled Londoners switch to cleaner vehicles.
  • Almost tripled the amount of protected space for cycling.
  • Implemented a zero-carbon homes standard in all new major residential developments, with developers committing to carbon emission reductions of 37% more than national building regulations. This policy  will be rolled out to non-domestic buildings in the new London Plan.   
  • Created a £50m fund to support a Green New Deal to reduce emissions and achieve net zero carbon by 2030.


However, Sadiq is not complacent and it is clear there is still more work to do to make sure Londoners are breathing the cleanest possible air. There are still many locations where pollution levels remain high - including for particulate matter - for example at the monitoring site in Vauxhall which preliminary research indicates may be being impacted by a nearby ventilation shaft from the Tube. The Mayor is working with TfL to trial innovative new approaches to reduce pollution which is transported from the Tube network to the air above ground via ventilation systems.


Notes to editors

The full air quality monitoring update is available here:


The EU sets legal limits for both short-term and long-term concentrations of NO2. The long-term limit is an annual average of 40 ug m-3. The short-term limit is an hourly average of 200 ug m-3 not to be exceeded more than 18 times per year before a legal breach occurs.


* The EU sets legal limits for both short-term and long-term concentrations of NO2. The long-term limit is an annual average of 40 ug m-3. The short-term limit is an hourly average of 200 ug m-3 not to be exceeded more than 18 times per year before a legal breach occurs.


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