The European Commission yesterday said it is taking Germany, Britain, France and three other countries to the bloc's highest court for failing to comply with EU air quality standards.
The decision by the commission, the 28-nation European Union's executive arm, hits Britain before it is due to leave the bloc in 2019 following the shock Brexit referendum two years ago.
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.
However, EU Environment Commissioner Karmenu Vella told a press conference in Brussels that the countries, part of what activists have dubbed a "toxic bloc", had failed to act quickly enough.
"The commission had to conclude that... the additional measures proposed are not sufficient to comply with air quality standards as soon as possible," Vella said.
"Consequently, the commission has decided to refer these (six) member states to the Court of Justice of the EU," the executive arm said.
The Luxembourg-based court can impose heavy fines.
The commission has been urging the wayward countries to establish incentives for the transport, energy and agricultural sector as well as improve urban planning and building design to improve on pollution.
The EU estimates that air pollution costs the bloc 20 billion euros ($24.7 billion) a year in health costs, but says this could be reduced if member states comply with agreed emissions limits.