Cars failing emission standards says Which

Consumer watchdog, Which has claimed that the New European Driving Cycle (NEDC) test, which is currently used to test emissions, is too lenient and can be exploited.

Which recently carried out realistic tests and found the majority of cars contravened emissions regulations.

All of the vehicles officially complied with recent EU emission regulations (either Euro 5 or the tougher Euro 6 depending on the age of car) but it said it found 95% of diesel cars, and 10% of petrol cars, emitted more NOx than limits allow.
The majority of petrol cars it tested also exceeded EU carbon monoxide (CO) limits, and even some hybrid cars exceeded NOx and CO limits.