Dutch airline KLM misled customers through advertisements that suggested its flights are climate friendly, an Amsterdam court ruled.

KLM makes climate claims in advertisements that are “based on vague and general statements about environmental benefits, thereby misleading consumers,” the district court of Amsterdam said in its judgment Wednesday. The carrier didn’t provide travelers with honest and concrete information, it said. 

The aviation industry is struggling with efforts to decarbonize as the options at its disposal remain limited. Airlines depend on using sustainable aviation fuels or buying carbon offsets, such as tree planting or land restoration, to demonstrate how they are reducing emissions. Yet, many of these steps are currently seen as inadequate. 

Air France-KLM’s dutch arm was one of the first major airlines to face a lawsuit over greenwashing, which refers to marketing that aims to falsely convince customers that a brand is environmentally friendly. It was sued by Dutch environmental pressure groups in 2022 over allegations that the airline’s “Fly Responsibly” campaign, with the tag line “Be a hero, fly CO2 zero” created a false impression of its climate impact. 

KLM paints an “overly rosy picture” of measures such as sustainable aviation fuels and reforestation which “only marginally reduce the negative environmental aspects and give the wrong impression that flying with KLM is sustainable,” the court said in its verdict. The airline has discontinued the ad campaign.

Air France-KLM’s Chief Executive Officer Ben Smith dismissed the claims of greenwashing. “It’s something we strongly believe we don’t do,” Smith said at an event in Brussels on Wednesday.