Jim McMahon/Mapman®

Paper or plastic? China wants neither. Earlier this year, the Asian nation banned the import of 24 kinds of recyclable waste, including plastic bottles, unsorted papers, and textiles.

Prior to the ban, China took in half of the world’s recycling—about 7.3 million tons in 2016 alone. It used the trash to fuel its huge manufacturing boom, recycling it into clothing and other items. (China has the second-largest economy in the world, after that of the United States.)

However, China says it’s no longer safe to keep taking the world’s trash. A lot of the recycling it receives includes hazardous nonrecyclable materials. Officials say that threatens the environment and the health of China’s people.

But the ban has caused headaches abroad. Several countries, including the U.S. and the United Kingdom (U.K.), sent part of their recycling to China because there’s simply too much to recycle at home. Now those nations are scrambling to deal with huge buildups of garbage while they look for better solutions to managing their waste.

“It’s tough times,” says Simon Ellin of the Recycling Association in the U.K. “We’ve got to start producing less, and we’ve got to produce better-quality recyclable goods.”