German automakers have offered to cut emissions by updating the software of 5 million diesel cars in an attempt to avoid vehicle bans.
The companies will install new engine management software to make emissions filtering systems more effective, the VDA industry association said.
Daimler, BMW, Volkswagen Group and Opel agreed to the overhaul, the VDA said.
The upgrades to Euro 5 and some Euro 6 models will rely on software patches rather than costly component fixes, with the aim of cutting emissions of smog-inducing nitrogen oxides by 25 percent to 30 percent on average, the VDA said in a statement.
The move should reduce pollution at least as much as driving bans proposed in major cities, the VDA said.
The offer came as top executives from the German auto industry met with ministers and state leaders in Berlin on Wednesday amid negative news about diesel pollution, prompting threats of driving bans in German cities to improve urban air quality.
Protests forced a last-minute change of venue for the talks. The summit was moved from the transport department to the more secured interior ministry after Greenpeace and other protesters descended on the transport ministry's offices. Activists hung a banner across the facade of the transport ministry proclaiming "Welcome to Fort NOX."
Despite the industry's software upgrade offer, the talks were still continuing on Wednesday and had broken into several groups, an insider source said.
BMW incentive offer
Separately BMW announced plans on Wednesday to offer owners of older diesel passenger cars designed to meet the Euro 4 or lower emissions standards a bonus of up to 2,000 euros when they trade in their vehicle for a new lower-emissions car.
The new vehicle would have to be either a BMW i3 electric car, a plug-in hybrid or a Euro 6-standard vehicle. The campaign will begin this month and initially run through the end of the year, BMW said in a statement.
Diesel was once the calling card of German auto-engineering prowess, with the industry boasting about the technology offering more power while emitting about a fifth less carbon dioxide than equivalent gasoline engines.