- Under EU rules, member countries are required to keep the gas to under 40 micrograms per cubic metre -- but that level is often exceeded in many traffic-clogged European cities.
BERLIN: The EU's top court ruled on Thursday that Germany continually violated upper limits for nitrogen dioxide, a polluting gas from diesel motors that causes major health problems, over several years.
Germany infringed air quality rules "by systematically and persistently exceeding" the annual nitrogen dioxide limit in 26 out of 89 areas from 2010 to 2016, the European Court of Justice (ECJ) said in its ruling.
The European Commission, the EU's executive arm, referred the matter to the ECJ in 2018 after almost a decade of warnings that went unaddressed.
The decision against Europe's top economy echoes a ruling targeting France in October 2019 after the commission stepped up its anti-pollution fight in the wake of the so-called "Dieselgate" scandal that erupted in 2015 with revelations about Germany's Volkswagen.
The motors caught up in the scandal -- in which automakers installed special emission-cheating devices into their car engines -- are the main emitters of nitrogen oxides that the European Environment Agency says are responsible for 68,000 premature deaths per year in the EU.
Nitrogen dioxide is toxic and can cause significant respiratory problems as one of the main constituents of traffic-jam smog.
Under EU rules, member countries are required to keep the gas to under 40 micrograms per cubic metre -- but that level is often exceeded in many traffic-clogged European cities.
The judgement opens the way to possible sanctions at a later stage. However the air quality throughout much of Germany has improved in the last five years, particularly during the shutdowns in the pandemic.
The environment ministry said that 90 cities exceeded national pollution limits in 2016 -- the final year covered by the court ruling. By 2019, the number had fallen to 25 and last year, during the coronavirus outbreak, it was just six.
The case involved 26 areas in Germany, including Berlin, Hamburg, Munich and Stuttgart as well as urban and rural areas in North Rhine-Westphalia, Mainz, Worms/Frankenthal/Ludwigshafen and Koblenz/Neuwied.
"Furthermore, Germany infringed the directive by systematically and persistently exceeding, during that period, the hourly limit value for NO2 in two of those zones" -- the Stuttgart area and the Rhine-Main region.