Over there they would refer to US cars as “Dreck Schleuder” (Filth slinger) and ironically this was years after in the US cars has catalytic converters, were running on unleaded fuel, and had pollution pumps. All the way into to 90s they were driving leaded and without catalytic converts for the most part, but that didn't stop them from snubbing their noses at American cars and calling them “filthy, uneconomical, polluting.... you name it.”
They had a point as I noted. Just once I saw a guy with a device which measured actual volume of pollutants put the thing on a GTA Alfa race car with just straight exhaust and then on a new Buick with every sort of pollution control, and this was in the mid 70s, and the Alfa produced less pollution. Once you get into the modern age of cars with computerized fuel injection of course, the German arguments break down.