As a result, recyclers have to add an expensive additional sorting step to divide different colors of PET, to avoid contaminating the clear PET bales of recycled material; and they get no return on their investment for baling up the blue and green stuff, because no one wants it.
That's why Japanese beverage makers phased out colored PET, way back in 2001. When neighboring South Korea followed suit, they found they doubled their recycling rate to 70%, according to Plastics News.
Here in 2021, Coca-Cola is finally catching up, and phasing out green PET for the Sprite brand. They've also announced that they're transitioning to 100% recycled PET across all brands. Better late than never.