Emissions of nitrogen oxides (NOx) fell 10% in 2016, reaching their lowest level since 1970, but environmental campaigners say more action is needed to tackle road transport pollution.

Although the report says national NOx levels are now in line with EU legislation, a number of towns and cities still exceed limits.

The report by the Department for Environment, Food and Rural Affairs (Defra) shows NOx emissions – which are particularly produced by road transport, especially diesel vehicles – were down by 72% in 2016 compared to 1970, reaching 0.89 million tonnes. The data also shows NOx emissions decreased by 23% between 2012 and 2016.

The report suggests that although the UK exceeded the current international and EU ceiling for nitrogen oxides in 2010, it came back into compliance from 2011 onwards, although individual cities are still exceeding limits.

According to the Government, the main reason for this decrease has been the closure of a number of coal-fired power stations. As a result, the figures show an increase in the share of NOx coming from road transport: 34% in 2015 and 49% in 2016. These emissions are largely from diesel vehicles, although recent months have seen diesel’s share of the overall new car and fleet sectors decline.

In response, ClientEarth – which took the UK government back to court three weeks ago over its latest air quality plans – said more work is needed to combat vehicle usage in urban areas.

Senior campaigner Andrea Lee commented: “The reduction in emissions is good news but it fails to tell the whole story. Concentrations of nitrogen dioxide are still at illegal and harmful levels in our towns and cities, where the majority of people are exposed to it. The Government needs to focus on urgently tackling illegal levels of air pollution with policies like clean air zones, targeted diesel scrappage schemes and other initiatives designed to help people move to cleaner forms of transport.”