(Reuters) - German cities are starting to introduce bans on older diesel vehicles that emit higher amounts of pollutants than later models after the country’s highest administrative court in February confirmed such bans are permissible.

A diesel fuel nozzle is seen attached to a car at a Shell petrol station in Berlin, Germany October 22, 2018. REUTERS/Fabrizio Bensch

Germany’s cities have for years flouted Europe’s clean air rules, prompting environmental groups to sue local governments in an attempt to force bans of some heavily polluting vehicles. The first diesel ban took effect in May in Hamburg.

Diesel car sales in Germany fell to 31.1 percent of the total in the first half of 2018 from 41.3 percent a year earlier, while in the European Union sales declined by 16 percent during the period.

After a court ruling in Mainz on Oct 24, on Thursday a decision was also reached in Bonn and Cologne, where old diesel vehicles are to be banned in certain areas of the cities.

Below is a summary of the rulings on diesel vehicles in various cities so far:

BONN AND COLOGNE

On Thursday, a court ruled that Cologne must introduce bans on older diesel vehicles in certain areas from April 2019. The nearby city of Bonn must impose bans for two roads.

MAINZ

A court ruled that Mainz, the state capital of Rhineland-Palatinate, must impose a driving ban on older diesel vehicles in September 2019, if nitrogen oxide and fine particulate matter pollution levels are not brought down to agreed limits. The city can appeal against the ruling.

STUTTGART

The state of Baden-Wuerttemberg plans to ban older diesel cars with engines conforming to the Euro 4 emissions standard, which stems from 2005, in Stuttgart in 2019. A ban on diesel cars adhering to the Euro 5 emissions standard, which applied to vehicles made from 2009, is still before the court.

AACHEN

A local administrative court in June said driving bans would be imposed unless values for nitrogen oxide pollution were met by the end of year.

FRANKFURT

From February 2019 diesel cars made to Euro 4 standard and older will be prohibited from entering the city center, the administrative court in Wiesbaden ruled in September. The air pollution control plan, to be updated by the state of Hesse, must also include a driving ban for diesel vehicles of the Euro 5 standard from September 2019.

BERLIN

In October, the administrative court ruled that by the end of June 2019, cars and trucks with diesel engines that comply only with the Euro 5 or lower emission standard, should not be allowed to drive on at least eleven routes.

MUNICH

In Munich, city authorities have not implemented a court ruling from February 2017, to ban some diesel vehicles on certain routes, despite facing fines for their failure to do so.

DUESSELDORF

In Duesseldorf a court ordered, as early as 2016, that a driving ban for diesel vehicles should be seriously examined. Despite that, in August 2018 the district government of the city presented a new air pollution control plan without driving bans.

Below are the German cities where regional courts are due to decide on the introduction of bans on diesel cars, along with the provisional ruling dates.

* Essen and Gelsenkirchen - 15 Nov 2018

* Darmstadt - 21 Nov 2018

* Wiesbaden - 19 Dec 2018