In a bid to avoid EU emissions fines, the German government is planning to trial free public transport to cut the number of private cars.

The move, which has been welcomed by transport experts, comes just over two years after Volkswagen's emissions scandal unleashed anger at the car industry.

In a letter addressed to EU Environment Commissioner Karmenu Vella and quoted on the Clean Energy Wire, German Environment Minister Barbara Hendricks, Finance Minister Peter Altmaier and Transport Minister Christian Schmidt write that “together with the [federal states] and the local level, we are considering public transport free of charge in order to reduce the number of private cars.”

Germany missed a January 30 deadline to meet EU limits on nitrogen dioxide and fine particles, but has been given extra time by Brussels to devise emission-cutting measures.

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

The proposal will be tested by "the end of this year at the latest" in five cities across western Germany, including former capital Bonn and industrial cities Essen and Mannheim, according to AFP.

Other steps proposed include further restrictions on emissions from vehicle fleets like buses and taxis, low-emissions zones or support for car-sharing schemes.

Life-threatening pollution affects more than 130 cities in Europe, according to the European Commission. It causes around 400,000 deaths per year.

Countries that fail to keep to EU limits could face legal action at the European Court of Justice.