In car-obsessed Germany, the government is considering free public transportation in some of its most polluted cities to reduce road traffic and emissions from private vehicles.

"We are considering public transport free of charge in order to reduce the number of private cars," three ministers wrote in a letter to EU environment commissioner Karmenu Vella in Brussels.

"Effectively fighting air pollution without any further unnecessary delays is of the highest priority for Germany," the ministers added.

A trial of the proposal is planned for the cities of Bonn, Essen, Herrenberg, Reutlingen and Mannheim "at the end of the year at the latest."

The letter was signed by German Environment Minister Barbara Hendricks, Agriculture Minister Christian Schmidt and Chief of Staff of the Federal Chancellery Peter Altmaier.

According to AFP, which first reported on the letter, other proposed measures include further restrictions on emissions from vehicle fleets like buses and taxis, low-emissions zones and support for car-sharing schemes.

DW reported that some of the cities selected for the free public transportation trials were unclear about the specifics of the proposal.

"It's not in the planning phase yet," a spokeswoman with the city of Bonn told DW. Rollout dates have yet to be announced and the federal government did not specify about how it will subsidize the free public transportation.

But Bonn Mayor Ashok Sridharan, who was informed about the government's plans over the weekend, said he was happy his city was selected as one of the "lead cities."

"We also have one or two ideas that we can also propose, since we've been working on this topic for some time," Sridharan told DW.

As the AFP noted, the proposal comes just over two years after Volkswagen's "dieselgate" emissions cheating scandal. The German company was forced to pay billions in fines and helped prompt its plans to electrify much of its fleet. Other carmakers, including fellow German brand Daimler, have since faced their own emissions scandals.

Last year, Volkswagen, Daimler and BMW announced a €500 million ($593 million) plan to upgrade more than 5 million newer diesel cars in Germany and offer trade-in rebates on older models. They have also agreed to pay into a public transit fund to reduce diesel pollution.

The government "should make sure that the car manufacturers finance the emergency measure" of free transport, Greenpeace told AFP.

Environment ministry spokesman Stefan Gabriel Haufe clarified Wednesday that the measure is not intended to help the car industry pay for cleaning up its polluting cars already on the road.

"In the long run, you can't reduce excess emissions levels in cities unless you cut nitrogen emissions from diesel engines," he said at a news conference. "We have seen speculations that we would like to reduce the burden on the car industry. That is absolutely not the case."