BERLIN -- Germany is doubling the funds to help municipalities avoid driving bans for old diesel vehicles to almost 2 billion euros ($2.3 billion), Chancellor Angela Merkel said.
The government had previously pledged 1 billion euros to help improve air quality, but after meeting with municipal representatives on Monday, Merkel said this program would be increased to 1.5 billion euros by 2020.
The chancellor said the federal government would also set aside an additional 432 million euros for hardware retrofits of small trucks with older diesel engines.
The government has been pushing automakers to shoulder more of the burden of retrofitting cars with insufficient exhaust filtering systems following scandals involving schemes to conceal the true levels of polluting emissions from diesel cars.
Environmental activists have sued municipalities and cities to force bans of heavily polluting vehicles in areas where levels of toxic nitrogen oxide violate European clean air standards.
One way to clean up older diesel cars is to fit more effective exhaust filters to cars. The issue of hardware retrofits, which municipalities want, was not resolved at Monday's meeting.
German Transport Minister Andreas Scheuer said his ministry would, by the end of 2018, present guidelines on manufacturing improvements that would help curtail nitrogen oxide emissions.
Scheuer said he expected it to take around six months after that to develop hardware retrofits and those would then need to be approved by the Federal Motor Transport Authority too.
Other German cities also face the risk of diesel driving bans imposed by judges, including Frankfurt, Aachen, Berlin, Stuttgart, Duesseldorf and Mainz.
The decisions were made after a landmark ruling by Germany's top administrative court in February that opened the door to inner-city bans.
Merkel said 249 German cities had NOx concentrations below the EU limit of 40 micrograms per cubic meter, while 65 cities had higher concentrations than that.
Of those 65 cities, 40 had a reading between 40 and 50 micrograms and should therefore not have driving bans because the measures already agreed are expected reduce the concentrations quickly, Merkel said.