The European Commission has opened an in-depth investigation of whether several major automakers colluded to avoid competition, it announced on Tuesday.
"The Commission is investigating whether BMW, Daimler and VW [Volkswagen, Audi, and Porsche] agreed not to compete against each other on the development and roll-out of important systems to reduce harmful emissions from petrol and diesel passenger cars," Margrethe Vestager, commissioner for competition, said in a statement.
"These technologies aim at making passenger cars less damaging to the environment," Vestager said.
"If proven, this collusion may have denied consumers the opportunity to buy less polluting cars, despite the technology being available to the manufacturers," she added.
The commission said the investigation will focuses on information showing those companies -- also called the "circle of five" -- participated in meetings where they discussed inter alia the development and deployment of technologies to limit harmful car exhaust emissions.
"The in-depth investigation will aim to establish whether the conduct of BMW, Daimler and VW may have violated EU antitrust rules that prohibit cartels and restrictive business practices, including agreements to limit or control technical development," the statement said.
"At this stage, the Commission has no indications that the parties coordinated with each other in relation to the use of illegal defeat devices to cheat regulatory testing.
"The Commission will carry out its in-depth investigation as a matter of priority," it added, noting that the opening of a formal investigation does not prejudge its outcome.