Hilton Holloway:

about to clear the way for the country’s local cities to legally drive older diesel cars off the road. And it’s not the first time German cities have moved to put the squeeze on older vehicles.
 
 At the beginning of 2008, a number of German cities and towns started to institute what were called low-emission ‘Umwelt’ Zones. To access these areas, your vehicle needed to have an engine with a Euro 4 pollution rating.