Volkswagen's emissions scandal seems to get more puzzling and entrenched by the day.

On Sunday, the New York Times reported that the European Commission knew that Volkswagen's diesel models were failing pollution tests years before its emissions scandal made headline news around the world last September.

How long did the European Union's executive branch know about it? Well, the Times says that the Commission had actually performed road tests, including emissions, on seven diesel models back in 2007, but it didn't report which automakers — nor their models — were involved with that testing when the report was published in 2011 and 2013.

The Times adds that the tests were intended to identify the shortcomings of holding pollution tests in labs, while also reviewing the equipment used to test emissions on the road.

The European Comission's Joint Research Center was responsible for testing the diesel vehicles, but that same division warns of people jumping to conclusions about the models tested being VWs.

"It must be noted that the vehicles used for the research cannot be considered representative of the general level of emissions by the models in question," Nina Kajander, a spokesperson for the Joint Research Center, told the Times. "These were scientific studies designed to compare different methodologies for measuring emissions in laboratories against those measured on the road."

The testing resulted in diesels emitting more nitrogen oxides on the road than in lab tests.

The Times adds that a VW Golf met emissions regulations when tested in the lab, but nearly tripled those limits when tested on the road. A car by Renault — the Cilo — nearly exceeded emissions limits by seven times.

It remains to be seen how this news will impact VW's European recall, which is currently in progress.