Berlin - The role of the German Transport Ministry in the massive diesel scandal that rocked the country's car industry over the past half-decade must remain under wraps for the time being. 

The anti-corruption organisation Transparency International (TI) says it has given up its fight and ceased its legal proceedings against the ministry headed by CSU politician Andreas Scheuer.

At a press conference Thursday morning, TI chairman Hartmut Bäumer said the ministry had undermined its efforts to get at the relevant information and had only released heavily redacted files. The anti-corruption organisation could take legal action against the ministry, but is refraining from doing so because of the high cost involved.

The legal dispute began in October 2018. At that time, TI wrote to Transport Minister Andreas Scheuer and requested disclosure of all information about defeat devices available to the ministry.

Defeat devices were installed in diesel cars by several German automakers in order to manipulate emissions during testing. TI wanted to discover which manufacturers had used which defeat devices in which models - only one model had been made public, the VW EA 189 engine.

However, it had already become clear in court that there were others. TI also wanted to know from the ministry which German manufacturers were obliged to pay fines because of illegal defeat devices. The information request was based on the Environmental Information Act and the Freedom of Information Act.

In November, the Ministry of Transport rejected the application and the legal dispute began. Scheuer commissioned a law and consulting firm KPMG to defend the ministry against the claims. The process dragged on for more than two years - until the ministry released 4,228 pages from its files in February. However, most of them were blacked out.

Transparency International decided to throw in the towel.  The law firm Partsch und Partner, which had represented the organisation pro bono until then, could no longer afford to do so in view of the effort involved and withdrew the lawsuit in June. The transport minister is now in a more advantageous position, thanks to the €300,000 of taxpayer money that KPMG has received for handling the case so far, according to TI. A Berlin administrative court has since discontinued the proceedings.

Hartmut Bäumer painted a bleak picture on Thursday: "It is shameful for the rule of law that Andreas Scheuer squanders hundreds of thousands of euros in legal fees to undermine citizens' justified claims for information." This undermines trust in politics and the rule of law.

The lawyer Christoph Partsch, the former corruption commissioner of the Berlin Senat, called for improvements in administrative procedural law.

In the wake of the defeat, Transparency International directed some clear demands to whoever forms Germany's next government. After the Bundestag elections, "a genuine transparency law must be introduced as an improvement on the Freedom of Information Act". This would require the authorities to release information and not make it the duty of citizens to fetch it.