(Bloomberg) -- Austrian Airlines AG was found guilty of misleading climate-conscious travelers by suggesting its flights were sustainable, even though they were largely powered by fossil fuels.

An Austrian consumer-protection association filed the suit against the Lufthansa AG’s subsidiary earlier this year over advertisements featuring sustainable aviation fuel. The airline claimed flights to an art show in the Italian port of Venice would be fueled with 100% sustainable fuel when, in fact, only 5% derived from renewable resources, according to a copy of the decision posted by Austrian Airlines on its X account.

The ruling by a commercial court outside of Vienna was made just as European Union officials crafted new regulations to ban misleading environmental claims made by companies on their products, or so-called greenwashing. 

“It isn’t technically possible at present to operate carbon dioxide-neutral flights with 100% sustainable aviation fuel,” the Association of Consumer Information’s lawyer, Barbara Bauer, said in a statement. 

Austrian Airlines was required to post a copy of the court verdict on its website and social media account where the original advertisement appeared, as well as pay for the consumer-protection association’s legal counsel. 

“It follows from the ruling that Austrian Airlines should have provided clearer information,” the company said in an emailed statement. “Austrian Airlines will take the ruling into account in current and future advertising statements.”

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