Mayor of London issues high pollution alert
The Mayor of London, Sadiq Khan, has triggered a ‘high’ air pollution alert for London tomorrow, Tuesday 10th November 2026.
Forecasters at Imperial College London advised the Mayor to issue the alert and Sadiq is encouraging everyone in the capital – particularly those who are most vulnerable - to look after themselves and for everyone to do their bit.
High levels of particle pollution are forecast for Tuesday after dense fog and very light winds allowed pollution to build up over the weekend and linger into Monday morning. Smoke from Bonfire Night and Diwali fireworks and from wood burning is likely to have contributed.
All Londoners can do their bit to reduce air pollution by:
- walking, cycling and using public transport more frequently, avoiding the busiest roads when you can
- driving less, and when you do drive, drive smarter – car share if you can, turn your engine off when you're not moving, and keep your vehicle well maintained
- composting or taking garden waste to a refuse centre rather than burning it
- avoiding unnecessary burning at home – for example, using a wood burner or open fire
This is the fourth high air pollution alert this year. Additional details have been shared with London’s GPs and emergency departments, to ensure that they have crucial information to help vulnerable patients.
City Hall issues alerts to Londoners, schools, and London boroughs when moderate, high or very high air pollution is forecast. High air pollution alerts are also displayed at public locations across London, including all bus stop countdown signs, as well as on the Underground.
The Deputy Mayor for Environment and Energy, Mete Coban said: “Toxic air is responsible for thousands of premature deaths in London each year, which is why the Mayor has done everything in his power to tackle it, which includes launching the world’s largest clean air zone.
“It is really important we all do our bit to protect those who are most vulnerable as we continue working to build a safer and greener London for all.”
Notes to editors
- The moderate and high daily thresholds are based on Defra’s national Daily Air Quality Index (DAQI). These thresholds are substantially above the World Health Organization’s air quality guideline values and indicate pollution levels at which short-term health effects may occur, particularly for people with pre-existing conditions such as asthma or chronic obstructive pulmonary disease (COPD).
- Particulate Matter (PM) is a transboundary pollutant and therefore concentrations are heavily influenced by meteorology, background concentrations and sources outside of London, including on the continent, on top of local emissions.
- In 2016, the Mayor set up a system to warn Londoners about moderate and high pollution episodes. These forecasts are created by Imperial College London, and checked against other public forecasts (airTEXT, Met Office, London Air) to predict when air pollution in the capital will reach moderate, high or very high levels.
- In 2024, the Mayor expanded the alerts system coverage to also go to NHS GPs and Emergency Department consultants, in order to support the health and care system across London in advising vulnerable patients.
- More information about the alerts can be found here: https://www.london.gov.uk/programmes-and-strategies/environment-and-climate-change/pollution-and-air-quality/monitoring-and-predicting-air-pollution