This story was originally published by the Guardian and is reproduced here as part of the Climate Desk collaboration.

New diesel cars from Renault, Nissan, Hyundai, Citroen, Fiat, Volvo, and other manufacturers have been found to emit substantially higher levels of pollution when tested in more realistic driving conditions, according to new data seen by the Guardian.

Research compiled by Adac, Europe’s largest motoring organization, shows that some of the diesel cars it examined released over 10 times more NOx than revealed by existing E.U. tests, using an alternative standard due to be introduced later this decade.