The new line—priced between $6 and $100—will be made with recycled polyester and recycled cotton, and will include two vintage biker jackets, which will be Boohoo’s first foray into the vintage market.

But despite Kardashian and Boohoo’s move to imbue fast fashion, an industry with an outsize environmental footprint, with a more sustainable image, the pairing quickly garnered online backlash from people accusing the brand and the influencer of “greenwashing.”

Many accused Kourtney’s personal brand of being “synonymous with excess” and called out Boohoo for creating a marketing campaign that leads to more waste.

And sustainability consultants in the fashion world agree. “You don’t have to be an expert to see that a sustainable ‘capsule collection’ is greenwashing,” Katherine Nasteva, a fashion expert at Lozena Sustainability Consulting, told Fortune.

Lisa Bergstrand from Bergstrand Sustainability Consultancy argues that Boohoo “does not provide any measurable commitment” towards its sustainability practices. “Not for Mrs. Kardashian Barker’s collection, not for any of their collections. So in that regard, I would say the backlash is warranted,” Bergstrand tells Fortune.

Bergstrand argues that the word “sustainable” no longer has any meaning in the fashion world, and that it is getting harder for anyone to do good “when the language we use to describe ‘good’ has been colonized by marketing departments trying to sell us more things we do not need.”

She concludes, “If Mrs. Kardashian Barker would like to understand more deeply about sustainability before putting her name on another collection, I would happily give her a workshop about it.”

The “sustainable” line

According to fashion trade magazine WWD, even Kourtney Kardashian Barker was wary of collaborating with Boohoo due to the fast fashion industry’s spotty environmental track record.

“When Boohoo first approached me to collaborate on a line, I was concerned about the effects of the fast-fashion industry on our planet,” Barker said in a statement seen by WWD. But Boohoo told her that it had a desire to incorporate sustainable practices for the collection, and Kardashian Barker wanted to use her platform to drive conversations on the topic.

“There’s still lots of work to be done and improvements to be made, but I truly believe that any progress we can make when it comes to sustainability is a step in the right direction and will open up the conversation for future advancements,” Kardashian Barker said.

But sustainability experts still have concerns with the line itself.

Selina Ho, founder & CEO of sustainable fashion consultancy Recloseted, said she “was really disappointed to see this collaboration from Boohoo,” and argued that if the brand really wanted to create a sustainable capsule collection, they should have collaborated with a slow fashion content creator—that is, influencers who talk about thrifting, mending, and buying well-made clothes from sustainable retailers.

Ho argues that if the collection has 46 pieces, that is not a capsule collection, “that is a full-on line.” She notes that “in the sustainable fashion space, less is more,” and says that with clothes priced as low as $6, she is skeptical about their margins and whether they are designed intentionally and for longevity.

She also argues that the mentions of recycled polyester and cotton don’t go into much detail, especially as recycled polyester takes a lot of energy to create and emits more microplastics when washed. “I would’ve loved to see them create a capsule without synthetic fibers, given this project’s budget and the capacity to push industry norms,” Ho tells Fortune.

Fast fashion’s bad stats

It is no doubt that fast fashion is immensely popular among young shoppers who look for cheaper alternatives to luxury fashion designers—and ones that seemingly arrive minutes after being ordered. But the industry is awash in poor statistics.

Fast fashion generated more CO2 than aviation and shipping combined in 2019, according to the U.K. government’s House of Commons Environmental Audit Committee, and contributes around 10% of the global carbon emissions, a U.N. report published in 2018 found. Over a third of all microplastics released into the world’s oceans are from synthetic textiles, according to fashion watchdog Common Objective.

Beyond its energy-intensive production, the textile sector also represents around 10% to 20% of global pesticide use, according to McKinsey’s State of Fashion report in 2020; and textile dyeing contributes around 20% of global wastewater, the UN Environment Program reports.  

Among the worst culprits, fast fashion brands like Fashion Nova, Boohoo, Revolve, Pretty Little Thing, and Forever 21 all score less than 10% on the Fashion Transparency Index.

“Boohoo is an ultra-fast fashion brand—the speed and frequency that its business model is based upon makes it inherently damaging, environmentally and ethically,” says Nasteva from Lozena.

Boohoo did not respond to Fortune‘s request for comment by the time of publication.