Britain’s car industry has hit back at government claims that diesel cars, on average, produce an amount of nitrogen oxide (NOx) six times higher in real-world driving than the legal limit used in official tests.

The defense of diesel cars comes after Transport Secretary Chris Grayling made front page news saying motorists should be wary of buying diesel vehicles, and suggested that an imminent clampdown on air pollution would encourage a switch to cleaner cars.

His claims came following a government report released a year ago. But the motor industry has dismissed recent criticism and claim the current models are the cleanest in history.

Now there is a suggestion that, actually, diesel cars could play an important role in tackling air pollution, as towns and cities look to implement stricter measures against polluting vehicles.

In fact, the Society of Motor Manufacturers and Traders (SMMT), argue the report, along with other recent studies on diesel cars, failed to differentiate between the current fleet of diesel vehicles and their older counterparts.

Unlike the latter, the former complies with Euro 6 emissions standards and most of the modern diesel cars are fitted with a system that transforms NOx into nitrogen and water – both environment-friendly – before it is released from the exhaust.

SMMT chief executive Mike Hawes said: “Euro 6 diesel cars on sale today are the cleanest in history. Not only have they drastically reduced or banished particulates, sulphur and carbon monoxide but they also emit vastly lower NOx than their older.”

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