(Bloomberg) -- KLM will need to defend its ad campaign promoting climate-friendly flying in court over greenwashing allegations after an Amsterdam judge paved the way for a full trial. 

The Dutch arm of Air France-KLM’s advertisements “breach EU consumer law standards by creating a false impression that its flights do not contribute to the worsening climate emergency,” environmental campaigners Fossielvrij and Reclame Fossielvrij, who sued the airline, said in a statement on Wednesday.

The claim comes after the Dutch advertising watchdog ruled last year that a KLM promotion telling customers they could fly carbon-emission free was misleading. KLM was then sued by Dutch environmental pressure groups which allege its Fly Responsibly ad campaign amounts to greenwashing.

KLM Accused of Greenwashing in Suit on ‘Fly Responsibly’ Ads 

Airlines have been buying carbon offsets, or offering customers the option pay extra for them, to convince travelers that their trips won’t contribute to global warming. These programs, which include tree planting and forest protection, have been criticized as insufficient, misleading or impossible to validate. 

“KLM is ambitious when it comes to its climate approach and would like to involve its customers in the subject,” a company spokesperson said. “We are learning more and more about communication on sustainability, and we keep looking at our communications to determine what can be improved and made even more transparent.”

Although KLM has discontinued its Fly Responsibly ad campaign “it has not made any commitments regarding its future advertising, nor has it addressed the carbon offset marketing that is also targeted by the lawsuit,” the groups said.

The lawsuit also challenges “KLM’s claim that the company is ‘creating a more sustainable future’ because of its net zero by 2050 target, which is at odds with its plans for continued business growth.”

--With assistance from Diederik Baazil.

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