Stuttgart, the home of Porsche & Mercedes-Benz banning older diesel vehicles

The decision is to enforce the Euro 4 or older emissions standards starting in January 2019, the state ministry of Baden-Wuerttemberg said on Wednesday this week.

There has been a global backlash against diesel cars since Volkswagen Group admitted in 2015 to cheating exhaust tests meant to limit emissions of particulate matter and nitrogen oxide (NOx). Dozens of German cities including Hamburg

, Munich and Stuttgart exceed European Union limits on NOx, which is known to cause respiratory diseases.

If by mid-2019 it does not look like the measures Stuttgart has taken to improve air quality will bring its NOx levels within the legal limits, the ban could be widened to Euro 5 diesels in January 2020, the Baden-Wuerttemberg ministry said.

Germany’s top administrative court ruled in February in favor of allowing major cities to ban heavily polluting diesel cars. Soon after, Hamburg became the first German city to ban diesel cars that do not meet the latest Euro 6 standards from some busy streets, seeking to raise pressure on carmakers to undertake costly retrofits. A regional court in Stuttgart had demanded last month the state of Baden-Wuerttemberg, home to carmakers Mercedes-Benz and VW unit Porsche, draw up a firm plan for when it will ban Euro 5 diesels.

Bans on diesel vehicles from city centers are also planned in Paris, Madrid, Mexico City and Athens by 2025, while the mayor of Copenhagen wants to bar new diesel cars from entering the city center as soon as next year. It will take at least another 10-15 years before ASEAN starts a ban like this.