https://phys.org/news/2018-09-german-car-surges-emissions-crunch.html

Industry observers point to the September introduction of the so-called "WLTP" emissions testing standard in the EU as a factor pushing carmakers to offer deep discounts or register vehicles to local sellers in August.

The popularity of diesel cars—whose manipulation to appear less polluting by Volkswagen and other firms prompted the push for WLTP—remains squeezed in Germany, with the fuel accounting for 32.6 percent of new registrations.