Progress on improving air quality in Britain's largest cities has stalled, according to a report published this week by the Clean Air Alliance. The study, which analysed data from monitoring stations across twelve urban areas, found that nitrogen dioxide concentrations have barely changed since 2023, despite a series of government pledges to accelerate the transition to cleaner transport.
London, Birmingham and Manchester showed the most concerning trends. In parts of central London, NO2 levels remain above World Health Organisation guidelines on more than 60 days per year. The report's lead author, Dr Elena Marchetti, said the findings pointed to a "policy gap" between stated ambitions and actual delivery. "The Ultra Low Emission Zone has made a real difference in the central area, but the benefits haven't spread outward the way the modelling suggested they would," she told reporters at a briefing in Westminster.
The government's Clean Air Strategy, published in 2021, set a target of halving the number of people living in areas exceeding WHO limits by 2030. At current rates of progress, the Alliance estimates that target will be missed by a margin of around 40 per cent. A spokesperson for the Department for Environment, Food and Rural Affairs said the government remained "committed to improving air quality across the country" and pointed to the forthcoming Zero Emission Vehicle mandate as evidence of continued action.
Environmental lawyers at ClientEarth, who successfully sued the government over air quality failures in 2015 and 2016, said they were "closely monitoring" the situation and had not ruled out further legal action. The full report is available on the Clean Air Alliance website.