The European Commission has told BMW, Daimler and VW that, in its preliminary view, that they breached antitrust EU rules over the development of engine emissions technology.

It says the manufacturers participated in a collusive scheme, in breach of EU competition rules, to limit the development and roll-out of emission cleaning technology for new diesel and petrol passenger cars sold in the European Economic Area.

This denied consumers the opportunity to but less polluting cars, despite the technology being available to the manufacturers.

Commissioner Margrethe Vestager said: "Companies can cooperate in many ways to improve the quality of their products.

“However, EU competition rules do not allow them to collude on exactly the opposite: not to improve their products, not to compete on quality.

“We are concerned that this is what happened in this case and that Daimler, VW and BMW may have broken EU competition rules.

“As a result, European consumers may have been denied the opportunity to buy cars with the best available technology. The three car manufacturers now have the opportunity to respond to our findings."

In particular, the Commission has concerns regarding the following technologies:

• Selective catalytic reduction (SCR) systems to reduce nitrogen oxides emissions of diesel passenger cars through the injection of urea (also called AdBlue) in the exhaust gas stream. In the Commission's preliminary view, BMW, Daimler and VW coordinated their AdBlue dosing strategies, AdBlue tank size and refill ranges between 2006 and 2014 with the common understanding that they thereby limited AdBlue-consumption and exhaust gas cleaning effectiveness.
• 'Otto' particle filters (OPF) to reduce harmful particle emissions from the exhaust gases of petrol passenger cars with direct injection. In the Commission's preliminary view, BMW, Daimler and VW coordinated to avoid, or at least to delay, the introduction of OPF in their new (direct injection) petrol passenger car models between 2009 and 2014, and to remove uncertainty about their future market conduct.

The Commission said this investigation is limited to an alleged violation of competition law. It is not about possible breaches of environmental legislation.