The U.S. Environmental Protection Agency (EPA) have accused automaker Volkswagen of installing software on certain Volkswagen and Audi diesel vehicles, which allowed them to detect when they were being tested and activate pollution controls to pass emissions tests. According to reports, the “defeat devices” allowed models to release up to 40 times more than the allowed amounts of harmful fumes in order to improve driving performance. The vehicles affected include the 2009-2015 VW Jetta, 2009-2015 VW Beetle, 2009-2015 VW Golf, 2014-2015 VW Passat, as well as the 2009-2015 Audi A3.

Volkswagen have announced plans to refit up to 11 million vehicles but did not say what the fix will be or how it could affect mileage and efficiency. As a result of the scandal, California’s Air Resources Board is now looking into other manufacturers’ testing results to see if other automobile manufacturers have been cheating on emission tests.