In a statement issued today (17 May), the EC said that it is referring France, Germany, Hungary, Italy, Romania and the United Kingdom to the Court of Justice of the European Union for failing to respect agreed air quality limit values and for "failing to take appropriate measures to keep exceedance periods as short as possible".
The commission had given the six countries - which also includes Italy, Hungary and Romania - a last chance in January to take long-sought steps to improve air quality or be hauled before the European Court of Justice.
"We have waited a long time and we can not possibly wait any longer", said Karmenu Vella, European commissioner for environment.
The World Health Organisation's director of public health, Dr Maria Neira, said new urgency was need to tackle air pollution: "While air pollution knows no borders and puts everyone at risk, those most vulnerable - pregnant women, children, the elderly, those already ill or poor- are particularly affected".
Today's announcement should surprise no one, the countries being sent to the court have had too many final warnings", said European Environmental Bureau Air Quality Policy Officer Margherita Tolotto, who added that "it is essential to understand why some governments, but not others. have been sent to court today. Toxic air results in more than 400,000 early deaths across Europe each year.
Germany, Britain and France were targeted for failing to meet limits on NO2 while Italy, Hungary and Romania exceeded limits on particulate matter. While being most acute in London, illegal levels of air pollution is a problem across the UK.
"We will shortly build on our £3.5bn plan to tackle roadside emissions with a comprehensive Clean Air Strategy setting out a wide range of actions to reduce pollution from all sources".
Warning that legal action alone will not solve the pollution problem, Mr Vella also unveiled a raft of new Commission measures to help member states promote cleaner air. But Commissioner Vella emphasised that they are not "off the hook" and the Commission will be monitoring their implementation progress closely.
It is unclear when the ECJ's jurisdiction over the UK's environmental concerns will end following Brexit.
The European Commission also issued a letter of formal notice to the United Kingdom for disregarding EU measures to deter vehicle manufacturers from trying to cheat emissions tests, introduced in the wake of the Volkswagen diesel scandal. The nations have two months to reply to prevent action from being escalated. "Manufacturers that keep disregarding the law have to bear the consequences of their wrongdoing".