Credit: CC0 Public Domain

Italy has "persistently and systematically" breached EU rules against small-particle air pollution, the European Court of Justice found Tuesday in a ruling supporting legal action by Brussels against Rome.

"Daily and annual limit values for PM10 particulate matter were very regularly exceeded" in zones highlighted by the European Commission in an infringement procedure launched two years ago, the court said in a statement.

Further, "the Italian Republic has manifestly failed to adopt in good time the measures" required under the EU's Air Quality Directive, which aims to reduce unhealthy pollution in Europe's air.

PM10 refers to the size of particulate matter in the air, with the number indicating how many microns, or tiny units of measurement, with one micron equalling 1000th of a millimetre in diameter.

The World Health Organization says air pollution of particles smaller than 10 microns can lodge in the lungs, and those smaller than 2.5 microns cause heightened mortality due to cardiovascular and respiratory disease and cancers.

The European Environment Agency estimates that 374,000 premature deaths occur annually in the EU from pollution with particles smaller than 2.5 microns.

The European Commission infringement process against Italy could result in fines being levied.

Several other EU countries are also in Brussels' sights for air pollution.

The European Court of Justice last year found France to be in breach of the Air Quality Directive for nitrogen dioxide levels, and last month the European Commission took Paris to court for fine particle air pollution.

Poland, too, was rapped by the court in 2018 for exceeding fine-particle levels.