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Diesels are "systematically"  releasing high amounts of nitrogen oxides into the atmosphere during real-world driving despite cars meeting the latest European regulations on emissions. 

That’s according to scientists from the International Council on Clean Transportation, an independent nonprofit based in Berlin, which has released the first results of a new initiative that it has conducted with a range of other organisations, including the FIA Foundation. 

The Real Urban Emissions Initiative (True) has today made public a ratings system that it says reflects real-world NOx emissions, and rates cars using a green/yellow/red (good/moderate/poor) scheme to reflect the levels of pollution. 

Automakers abandoning the diesel:

The True coalition says that it has tested around 4,850 models, ranging from Euro 3 to Euro 6 standards – astonishingly, all of the Euro 3, 4, and 5 diesels received a poor rating, and 91 majority of Euro 6 cars were also in the red. By contrast, all Euro 6 gasoline engines received a good or moderate rating. 

The study also found that four manufacturer groups had average emissions more than 12 times above the Euro 6 diesel type-approval limit and the highest-emitting vehicle family has emissions 18 times the limit.

Not only that, but all Euro 6 diesel models rated exceeded the Euro 6 diesel NOx emissions limits measured in real-world driving. The research also found that the highest-emitting gas Euro 6 vehicle family has approximately the same level of NOx emissions as the lowest-emitting diesel vehicle family.

All of the Euro 5 diesel models tests had NOx emissions at least twice the limit, with the worst one at 18 times the limit. 

True emissions results

"If I was a customer, I would look at these figures at the moment and have to conclude I should not buy a diesel car," said Peter Mock of the ICCT. "Even Euro 6 diesel vehicles are not performing well at the moment so pretty much all of them should not have access to city centers."

Mike Hawes, chief executive of the Society of Motor Manufacturers & Traders, said: "Thanks to massive investment, each generation of vehicle is more advanced than the last, with significantly lower pollutant emissions. This is acknowledged by the report, and consumers can be assured that new cars on sale today are the cleanest ever and fully compliant with EU emissions standards."

Diesel engines have steadily been declining in popularity since mid-2015, when it first emerged that Volkswagen had been fitting its cars with so-called cheat devices that enabled its cars to pass emissions tests in lab conditions while polluting on the road. Stricter legislation has since been introduced, but prominent cities have tables new rules that will see diesel-engined cars banned from certain areas. 

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