A consumer class action lawsuit filed Tuesday claims Delta Air Lines inaccurately billed itself as the world’s “first carbon-neutral airline” and should pay damages. The complaint in federal court in California alleges the airline relied on carbon offsets that were largely bogus.

Companies around the world buy carbon credits to cancel out their carbon releases with projects that promise to absorb carbon dioxide out of the air, or prevent pollution that would’ve happened. But they’ve been under the spotlight in recent months with claims their benefits are exaggerated.

The company is a big customer, purchasing credits from projects including wind and solar projects in India and an Indonesian swamp forest, the lawsuit says.

Delta spokesperson Grant Myatt described the lawsuit as “without legal merit.”

“Since March 31, 2022, (Delta) has fully transitioned its focus away from carbon offsets toward decarbonization of our operations, focusing our efforts on investing in sustainable aviation fuel,” Myatt said in an email. He added that the company is renewing its fleet with “more fuel-efficient aircraft and implementing operational efficiencies.”

The case, filed by Glendale, California resident Mayanna Berrin, claims to act on behalf of anyone who flew Delta while living in the state since March 2020. It says benefits from the offsets are likely to be temporary and would have happened even without the firm’s investment. For a carbon credit to be valid, it must provide a benefit that would not have happened otherwise.

Delta announced three years ago it would go carbon neutral, which means releasing no more climate-changing pollution into the air than it absorbs. It can also mean paying to guarantee it is absorbed elsewhere.

Berrin argues this enabled the firm to gain market share and charge higher prices. A writer for Nickelodeon, Berrin told The Associated Press she is about to enter her thirties and climate anxiety is pronounced in people her age.

“I felt comfortable paying more because I was neutralizing when I needed to travel for work or to see my family,” she said. She said she felt frustration and regret when she began having doubts about Delta’s offsets.

“They can’t just claim neutrality if that’s not factually accurate,” she said. “Lawsuits in general are very scary, and there are a lot of people who echo my frustrations who may not know their rights or the impact they can make by speaking up.”

Her attorney Jonathan Haderlein believes it’s the first such case against a major American airline, and one of just a handful of “greenwashing” cases in the U.S. based on consumer protection law.

The case number is 2:23-cv-04150.

In 2021 aviation made up more than 2% of global CO2 emissions, according to the International Energy Agency.