Two viewers challenged this claim as they believed that cars in the same class (a small family car), including the Toyota Prius and Renault Megane Hatchback, had lower emissions than the C4.
The ASA based its decision on the Department for Transport website “Act on CO2” section, which classes the C4 as a small family car. In this category, the C4 is ranked fifth for CO2 emissions at 120g/km, behind the Toyota Prius ranked first, and the Renault Megane Hatchback ranked third.
Citroen had based its claim about emissions on small family cars that had automatic gearboxes and diesel engines only. However, the ASA considered that viewers would understand the claim “the lowest in its class” to refer to a comparison with all vehicles in the small family car class, not just those specified in the comparison by Citroen.
A third complaint objecting to the ad for giving the impression that the C4 was more environmentally friendly than it was, was not upheld by the ASA. It noted that Citroen was one of the best car manufacturers for having achieved target reductions in CO2 emissions in vehicles since 1997.
Adverts for both Toyota Prius and Lexus RX 400h have been withdrawn in the last six months following the ASA upholding complaints about misleading comments in the ads, regarding the environmental impact of the cars.