But Vella also admitted that "legal action alone will not solve the problem".
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.
Germany, France and the United Kingdom were sent to the European Court of Justice for breaching EU standards for nitrogen dioxide limits.
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". Air pollution requires urgent action and it's been clear for too many years that authorities all across Europe are failing to protect their people from illegal and harmful levels of air pollution.
The EU's big polluters have received "sufficient last chances" but failed to clean up their acts, according to the bloc's environmental commissioner Karmenu Vella. The annual concentration of NO2 in London in 2016 was 102 micrograms per cubic metre of air.
But many member states, especially in major cities, regularly have air pollution far beyond these limits. But Commissioner Vella emphasised that they are not "off the hook" and the Commission will be monitoring their implementation progress closely.
The Commission said it was standing up for the right of citizens to breath clean air.
In light of the continuing fall-out from the Volkswagen Dieselgate scandal, the Commission is also taking action against four member states that "disregarded European Union vehicle type approval rules".
A summit was held in January to offer the countries a chance to find solutions to their air quality problems, but none offered "credible, effective and timely" solutions.
Especially in Germany, where the vehicle industry is considered one of the backbones of the country's economy, this decision might cause ripples.
"But it can not be in our interest to weaken the automobile sector to such an extent that it no longer has the strength to invest in its own future".