Outdoor photographer Zak Noyle has seen his share of marine debris, but he was shocked by what he discovered on an assignment in a remote spot off the coast of Java. There to cover Indonesian surfer Dede Suryana in 2012, Noyle found himself literally swimming in a sea of garbage. “It was overwhelming,” he recalls. “I really thought we were going to see a dead body in the water.”

Roughly eight million tons of plastic enters the ocean every year. That’s according to a 2015 report, which also identified where the bulk of this trash originates. At the top of the list: China, the Philippines, and Indonesia.

Sightings of junk-filled waters are common—and not only in Southeast Asia, says marine biologist Nicholas Mallos, who runs the Ocean Conservancy’s Trash Free Seas program. “Accumulations like this are unfortunately the norm,” he says, particularly in developing parts of the world where there are “rising middle-class populations along coastlines, and spending and consumption have increased, but waste management has not.”

Though trash remains a global problem, Mallos sees reasons to be hopeful. In the United States, for example, California voters in 2016 upheld a statewide ban on plastic bags. And in Indonesia, he says, there has been a shift in awareness: “We’re seeing an eager and willing group of stakeholders who are trying to step up and tackle these issues.” Put another way: The tide may be turning.

Originally published by National Geographic Magazine and by natgeo.com in April 2017.