London has not breached legal air quality limits for nitrogen dioxide (NO2) for the first time since records began.

The UK capital’s NO2 levels entered the third week of January below the legal average limit of 200 ug/m3 for nitrogen dioxide. The city has exceeded legal hourly air pollution limits by 6 January and often by 3 January every year for the past decade, since modern records began.

Exceeding the legal hourly air pollution limit requires a recording of 18 hours of very high pollution levels at any individual site.

The mayor’s office has attributed the phenomenon to measures such as the Toxicity Charge (T-Charge), which penalises for older, more polluting cars travelling in central London and introducing low emission bus zones around routes known for poor air quality.

Despite the improvement in air quality, London is expected to breach the legal NO2 hourly limit later this month.

“At long last we are seeing some improvements in our toxic air, but much more needs to be done before Londoners can finally breathe a proper sigh of relief,” said mayor of London, Sadiq Khan.

“I’ve made it my priority to safeguard Londoners’ health by targeting the capital’s most polluted areas and ensuring TfL have the funding needed to deliver the Ultra-Low Emission Zone and its expansion to help transform London’s air.

“But I can’t stop this health crisis without more help. Londoners deserve a government that wakes up to the scale of this problem and delivers tough new air quality legislation so that legal limits are met all year round.”

Khan also called on the government to introduce a scrappage scheme to remove older, more polluting vehicles from the roads.

“Instead of shamefully blocking the capital from accessing the new National Clean Air Fund, the government should be helping me deliver a vehicle scrappage scheme to firmly and fairly get the filthiest cars off our roads now.”