Svenja Schulze, Germany’s Environment minister, isn’t so sure that software fixes applied to diesel vehicles will completely resolve their emissions problems.

Speaking to German newspaper Tagesspiegel, Schulze said that the only way to avoid car bans is for diesel vehicles to be retrofitted with expensive hardware changes.

“I fear that in cities where the limits have been far exceeded – Munich, Stuttgart and others – software updates alone will not suffice. The many measures from the immediate program for clean air, such as electrification of buses, are good and will help many cities, but overall they aren’t enough to solve the problem in cities that are particularly badly affected.

“In my view [technical updates are the] only realistic way to avoid driving bans,” she said.

The German car industry supports 800,000 jobs

The minister continued by saying that retrofits are needed in particularly badly affected areas in roughly 20 cities, where software updates won’t be enough to control NOx emissions, Reuters reports.

Ever since the Volkswagen dieselgate scandal broke, there has been a strong backlash against diesels, particularly in Europe. Numerous cities have already announced driving bans for diesel vehicles, but German Chancellor Angela Merkel wants to avoid them alltogether.

In late February, the Federal Administrative Court in Leipzig, Germany ruled that cities across the country could ban older diesel-powered vehicles. In response, Stuttgart may ban Euro-4 vehicles next January and Euro-5 models in the fall of 2019. Moreover, other cities may introduce bans in the coming months if no other solutions can be found.