The Duke of Sussex has warned that the purchase of fruit and vegetables wrapped in plastic is a "dirty habit" that has "become normalised".
He questioned how it had become so common to buy peeled, pre-packaged vegetables, noting "it doesn't make any sense".
The Duke was speaking to a small group of young activists at a conservation event at Windsor Castle, spearheaded by leading primatologist Dr Jane Goodall.
He urged them to question supermarket staff about their packaging policies and the alternatives to plastic.
"I know Waitrose has spent a huge amount of money trying to find different ways to package stuff," he said.
"It doesn't make sense to find everything in plastic.
"Plastic within plastic. Gone are the days when you can just grab ten carrots, take them home and give them a shave.
"Now people are actually buying ten shaved carrots in a plastic bag. Why?
"We've slipped into this dirty habit and it's become normalised."
The Duke, echoing his father's concerns about plastic pollution, said those companies that had created the problem should take some responsibility and "spend the money they have made selling all this stuff" to clean it up.
"Even better stop making it and finding alternatives," he added.
The Duke had earlier greeted Dr Goodall, 85, famed for her life-long study of chimpanzees, with a "chimp greeting" having been taught it when the pair first met last year.
He delivered a speech at the global leadership meeting of her Roots & Shoots initiative, for which students from 26 countries had gathered for a week to work together on various projects.
Dr Goodall revealed that the Duke had asked to meet her last year and said she had met the Duchess of Sussex and their son Archie at Frogmore Cottage last month.
"She told me she's followed me all her life," she said of the Duchess. "She told me 'You've been my idol since I was a child. I've hero-worshipped you all my life.'"
"She came in at the end with Archie and I got to cuddle him. He's very cute and very gentle."
The Duke was also asked what peace meant to him and responded: "To be connected to the things that matter the most, rather than being disconnected."
He said a lack of human connection created "a lack of compassion and empathy for each other" which in turn prompted a lack of understanding about the importance of the ecosystem.
The Prince of Wales has long campaigned on the subject, warning last year that the younger generation deserved a better future than the "insanity" of a "damaged and destroyed world".