Diesel cars, the main problem is that they produce more smog-causing pollutants collectively called nitrogen oxides (NOx) than gasoline engines.
If the diesels are to survive, however, carmakers know they must produce engines that are cleaner during real driving and not just on the test bench.
That is why Krueger pointed out at Frankfurt that independent tests show his latest BMW 520d can also deliver low NOx emissions in a real-world setting and why he said: "I don't hold any stock in driving bans, sales bans or bans in general." Krueger's position on bans doesn't change the fact that BMW's home city of Munich isn't far behind Stuttgart in pollution, leaving diesel drivers facing a similar dilemma.
Twenty-eight areas in Germany regularly breach EU clean air limits when it comes to hazardous nitrogen dioxide (NO2), a major emission of diesel passenger cars. Dozens more high-pollution cities are found across the UK, France, Italy and Spain including all the major metropolitan centers led by London.