EU commission appeals Dieselgate ruling

"Our legal experts in the commission state there are legal grounds that justify an appeal," said Bienkowska.

"But I do not want to be wrongly understood. My focus is to get new legislation in place in time. I want you, parliament, to have a say," she noted.

Bienkowska promised that if the new legislation is adopted in time, the commission would withdraw the appeal.

The court ruling involves a 2016 decision related to a new measure of testing dangerous nitrogen oxide (NOx) emissions.

The new so-called real driving emissions test was able to more accurately measure the level of emissions - which were in reality much higher than the original test showed, leading to considerable damage to public health.

Carmakers successfully lobbied member states to accompany the introduction of the new test with a relaxing of the limits.

While under the old test the limit was 80 milligrams NOx per kilometre, the limit under the new test became 168 mg/km during a transitional period until 2020.

The EU's highest court said in December that this decision was made illegally.

Bienkowska spoke Wednesday in a public meeting with former members of the EU parliament's inquiry committee into the diesel emissions scandal known as Dieselgate.

They were not happy with Bienkowska's announcement.

"I am disappointed," said Belgian centre-left MEP Kathleen Van Brempt, the former chairwoman of the inquiry committee.

Fellow Belgian MEP Mark Demesmaeker, of the European Conservatives and Reformists group, also said he was disappointed, and said the decision was a "bad signal".

There appeared to be a difference in interpretation of the court ruling between the commissioner and the MEPs - all of whom have dealt with the Dieselgate issue extensively over the past years.

Bienkowska interpreted the ruling as being focused on the legal procedure which the commission had chosen - the so-called comitology method.

Under comitology, the role of the EU parliament is much smaller than under the ordinary procedure to adopt bills.

But MEPs were not so sure that it was only the legal method chosen which the court found fault with.

"In your remarks you said the court did not attack the principle of the conformity factor, but that is what they are ruling here, that the conformity factor is in effect not legal," said Labour MEP Seb Dance.

The conformity factor is the multiplication by which the original emissions standard has been stretched.

But Bienkowska was certain.

"The ruling was about the process, not about the content," said Bienkowska.

"I am 100 percent sure about this," she added.

Buying time

What the commission, which has to avoid a legal vacuum, is doing by appealing, is buying time.

If it had not appealed, a 12-month period to replace the annulled law would have started.

There are parliament elections in May, which will be followed by the end of this commission's mandate at the end of October.

Bienkowska said that she would send the EU parliament and the national governments the new legislative proposal soon.

"I want to make one thing clear. I want and I will do my best to have the legislation in place in the course of this year," she said.

"If the adoption of new legislation is in time then we can withdraw the appeal. This is my commitment. We can withdraw the appeal any time," she added.

But such a legislative proposal will need consent from both parliament and EU governments, and often takes longer than a year.

One could also argue that regardless of what test you use, that should not affect the emissions limits, agreed already in 2007.

Dutch Green MEP Bas Eickhout did as much.

"We don't need new laws. We just want to keep the current standards," he said.

He was supported by a colleague from the UK.

"Do you honestly think that this parliament would then pass legislation to lower the emission targets, given everything we said about this issue?," asked Dance.