FRANKFURT (Reuters) – The German government wants carmakers to offer mechanical modifications to engine and exhaust systems for some models, Der Spiegel reported on Saturday.

The new government position was agreed by experts and civil servants of the German transport ministry in an effort to prevent bans on diesel cars in some cities. The move would be a break with a less costly software-only overhaul agreed just months ago.

In August, German politicians and car bosses agreed to overhaul engine software on 5.3 million diesel cars to cut pollution and try to repair the industry’s battered reputation. Politicians stopped short of demanding more expensive hardware adaptations.

Environmentalists have said that agreement – two years after Volkswagen (VOWG_p.DE) admitted to cheating U.S. diesel emissions tests – was too little, too late, and have vowed to press ahead with legal action aimed at banning polluting vehicles.

The German transport ministry was not immediately available for comment.