Stuttgart, the home of Mercedes and Porsche, is to become the latest city in Germany to introduce a ban on some diesel vehicles – but has come under fire for only banning Euro 4 and older diesels from the outset.

The Stuttgart ban comes after Germany’s highest administrative court ruled that cities can ban diesel cars

The ban, which follows legal action by environmental groups, will come into effect from 1 January 2019 and will apply to the city centre. It follows clarification two months ago from the German Federal Court that cities are now officially allowed to ban older diesel vehicles from their streets, which has since led the announcement of a diesel ban on two streets in Hamburg.

The state government of Baden-Württemberg said the ban would initially apply to Euro 4 diesels and could be expanded to cover Euro 5 diesels if NOx levels did not fall to legal limits.

ClientEarth and Deutsche Umwelthilfe (DUH), which brought the original legal action, said the plan outlined is a step forward, but said they believe delaying restrictions on Euro 5 diesel vehicles fails to meet an order from the Stuttgart administrative court.

ClientEarth lawyer Ugo Taddei said: “A citywide ban on diesel cars up to Euro 5 in the home of German diesel sends a strong message – both in Germany and across Europe. But the vague plan to ‘see how it goes’ before banning Euro 5 vehicles is sloppy.

“The court made it plain and simple – Stuttgart’s authorities cannot duck their legal duty to bring air pollution down to legal levels. This proposal still does not look like it will meet the court’s standards and we expect to see a fine imposed. The fight for clean air stops only when we have decent, ambitious pledges to bring pollution down.”