The European Commission is taking Britain, France, Germany, Hungary, Italy and Romania to the EU Court of Justice for failing to respect air quality limits.
The move follows a summit in January in which the Commission said it would get tough on member states that were still in breach of targets.
The European Environment Commissioner, Karmenu Vella, said it was the Commission’s responsibility to ensure people could breathe clean air.
The European Court of Justice (ECJ) has the power to impose multimillion euro fines if the countries do not address the problem swiftly.
Read more