If things go according to the Greens in the European Parliament, they will all be called to explain themselves: representatives of the car industry, of the European Commission, and of those authorities in the EU's member states that are responsible for enforcing that emission limits are adhered to. Who cheated how, and to what extent, who knew about it at which point in time, and why didn't they do anything about it: these are essentially the questions the Greens want answered.

"This committee needs to establish the links between the European institutions and the car manufacturers," says the Green's Bas Eickhout. "And in the end, we do want to know who was responsible for what."

Inquiry committee a result of 'Dieselgate'

These are the questions that have come up since September last year - since the Environmental Protection Agency (EPA) in the United States started investigating German carmaker Volkswagen (VW). VW's diesel cars, an NGO found out, were meeting limits for emitting harmful nitrogen oxides in lab tests, but they were exceeding them under real driving conditions.

Following these findings, VW admitted to having systematically cheated on the lab tests. Currently, the EPA is investigating the carmaker for a violation of US laws against air pollution, with cars under examination ranging from VW's mid-sized Golf to Audi's Q7 SUV.

Bigger than VW

But for the EU, the scandal goes far beyond VW's cheating. That is partly because, in the meantime, NGOs have found that the vehicles of most major European car makers pollute the air more than they should when driven on the road in normal conditions, as opposed to test conditions in a lab.

"It's hard to pin-point one 'good' car manufacturer," says Jürgen Resch of NGO Deutsche Umwelthilfe. "We're still waiting to find one."

Brussels-based NGO 'Transport and Environment,' of which Deutsche Umwelthilfe is a member, says that Renault, Peugeot, Mercedes-Benz, BMW and Fiat were among those manufacturers whose cars were found to be emitting more on the road than in the lab.

Systemic failure exposed

In the wake of the VW scandal, moreover, the failings of an entire system have become apparent. How the EU arrives at rules for emission testing, what kind of rules it sets down, how it leaves testing in the hands of authorities in the member states: the system proved to lend itself to methodical cheating.

It is a systemic failure with real effects for EU citizens: 72,000 Europeans died prematurely as a result of exposure to nitrogen dioxide in 2012 alone, according to a report by the European Environment Agency.

Failure as a result of successful lobbying?

Nevertheless, there is a reason the EU system on emissions is as it is - and that reason has to do with the power of the car industry, critics allege.

According to watchdog Corporate Europe Observatory, the car lobby is one of Brussels's biggest, spending some 18 million euros in 2014 to influence the EU's trade, transport, climate and energy policy. Aside from that, there is also the role of the car industry in individual member states, such as Germany, France and Spain.

A December 2015 report by UK-based non-profit InfluenceMap for the Greens party in the European Parliament found that individual manufacturers as well as auto industry trade associations have exercised their influence to oppose the implementation of stricter emissions testing, as well as to argue successfully for allowing cars to exceed existing emission limits once stricter emissions testing does get introduced.

Some 12 million people in the EU worked in the car industry in 2012, with the industry contributing a share of 5.6 percent to the bloc's total employment.

Breaking the 'industrial-political complex'?

The inquiry committee, which is scheduled to have its first meeting in three weeks time and to wrap up its work in March next year, may therefore soon find it has embarked on a challenging mission.

"I am expecting this committee to really break the industrial-political complex we have in the automotive sector," says Jürgen Resch of Deutsche Umwelthilfe.

But the conservative politicians whose EPP group holds a majority in the parliament and who were opposed to establishing the inquiry committee in the first place, warned against the committee's work becoming a "witch hunt against the European automotive industry."

The EPP spokesman Krisjanis Karins warned his group would be watching that the committee "sticks strictly to its mandate."

Observers say that the inquiry's committee success or failure hinges on the Social Democrats, and whether they decide to side with the conservatives to limit the scope of the inquiry, or with the Greens and others favoring as broad and fundamental an investigation as possible.