Little Kamikatsu was facing a big problem. The rural Japanese town of 1,500 residents didn't know what it was going to do with its trash. Residents had always burned it, first in front of their homes or on the farms, then in a large community pit, then in an incinerator the government quickly banned out of fear of pollutants. The town didn't have money for a newer, safer incinerator. It had to find a new way.

"They had to look into zero waste," said Akira Sakano, chair of the board of directors of the Zero Waste Academy, an educational institution in Kamikatsu, explaining the discussions of those days in the early 2000s.

That research introduced the town to what was then a virtual unknown but has since grown into one of the most widespread and successful recycling efforts in history, bringing cities the world over to the precipice of what once seemed fantastical: the elimination of waste. Today, places in rural Japan to metropolitan Sweden send very little of their trash to the landfill. Many more - including Washington, D.C. - have a "Zero Waste" plan. In the United States, San Francisco leads the way, diverting more than 80 percent of its waste - two and a half times more than the national average. It has become a lifestyle, with millions of images flooding Instagram touting a #zerowaste existence, and generating new businesses.

The concept calls on people to think differently about waste. It starts with the creation of categories. There are recyclables, like aluminum cans and glass bottles. Reusables such as clothing. Compostables such as uneaten food. And then those that shouldn't be used at all such as plastic bags, which are very difficult to recycle. The number of categories might expand or contract depending on the location, but the goal behind the zero waste philosophy is the same: to vastly reduce the amount of trash going to the landfill - "diverting" it, in the parlance of waste experts, away from landfills and incinerators.

Debbie Raphael, director of the San Francisco Department of the Environment, who oversees the city's zero-waste initiative, said it's top-down and bottom-up. In San Francisco, there are three bins, one for recycling, one for compost and one for the landfill. The categorization is left to residents, and the sorting is left to the city contractor, Recology. "It takes policy," Raphael said of the zero-waste philosophy, which has purportedly cut the city's waste in half. "It takes financial incentives. It takes consequences for not participating. And it takes an ethic . . . of a sense of responsibility for the health of our planet."

It is a planet drowning in trash. Every year, the world is making more of it. In 2016 alone, the world's cities produced more than 2 billion tons of solid waste. Americans produce a disproportionate amount, throwing away the equivalent of their own body weight every month. And as the planet's population grows, the problems are poised to become significantly worse. Large landfills, according to a Washington Post project on trash, get as many as 10,000 tons of waste every day and are filling quickly. Within three decades, trash will outweigh fish in the ocean, according to the World Economic Forum.

If zero waste has an origin story, it would wind back more than 40 years to a man in Berkeley, California, named Dan Knapp. At the time, he was out of sorts. He'd just lost his job. His wife had left him. He was living with a college buddy in town, having just hitchhiked from Eugene, Oregon. And he couldn't stop thinking about trash. "My curiosity was inflamed," he said.

A former college professor with a PhD in sociology, he rode his bike to the Berkeley landfill nearly every day and scavenged - hands going through refuse for valuable metals, mind going through big questions. Where does all of this stuff come from? In the chaos of a landfill, could order be found? Patterns began to emerge, and from those patterns, categories. Here were the textiles. And the glass piles. And rotting food. And soil hauled from construction sites. This wasn't at all what he'd expected. He'd thought he'd find a bunch of unusable stuff. But it was an untapped resource.

Recycling, he realized, could go way beyond what was then a lofty goal of 35 percent, beyond aluminum cans and paper. Our trash just needed to be categorized appropriately, he said. Recycling shouldn't be made simple. It should be made complex. The thought ultimately led to a taxology of trash - called the "12 master categories of recyclable materials" - laying some of the initial groundwork for the "zero waste" concept.

But few people were listening. Knapp was just another Berkeley environmentalist - long hair, beard, the works. It took a city on the other side of the world, working on a plan that seemed stripped from the pages of the hippie manual. "In a natural ecosystem there is a balance," began "No Waste by 2010," a plan that Canberra, Australia, initiated in 1996. "The wastes from one process become the resources for other processes. Nothing is wasted. In a consumer society waste is an accepted part of life. A strategy is needed to reverse this trend."

Knapp, the owner of Urban Ore, which salvages Berkeley's waste, said he was flown in as a consultant to advise the city. He brought back the town's plan and soon was passing it around. He'd been calling his idea "total recycling." But here was something much catchier, right there on the plan's cover: No Waste, which quickly transformed to "zero waste," according to interviews with environmentalists. "Dan was very instrumental in bringing [the plan] over," said Neil Seldman, an official with the Institute of Local Self-Reliance in Washington.

But Canberra's plan accomplished more than that, said Paul Connett, a retired professor at St. Lawrence University who wrote, "The Zero Waste Solution: Untrashing the Planet One Community at a Time." People took the idea seriously for the first time. "It wasn't an activist talking about zero waste," he said. "It was a government law. All of a sudden, it became a topic of conversation."

One town in the early 2000s where it had become a topic of conversation was Kamikatsu, on the island of Shikoku, where the categories had been taken to an almost absurd level. The town had created 34 categories of waste disposal, possibly more than anywhere in the world. It asked people to differentiate between metal caps and aluminum cans, between milk cartons and paper cups - hewing as close as possible to the notion that the enemy of recycling is bad recycling. When a piece of plastic gets mixed with paper, or some metal mixes with glass - or, worse, something not recyclable is tossed in - it can lower the quality of the recycled product.

Sakano, of the Zero Waste Academy, said it may sound counterintuitive, but making recycling more complicated made it easier. "This is an aluminum can," she said. "This is a glass bottle. Clear color. Other colors. Newspaper. Cardboard. Paper tubes . . . It's all about putting the right product in the right places because mixture and contamination is the [biggest] challenge of waste recycling."

The town's residents compost in their homes, then haul their own trash to the town's collection center for additional sorting. Here, they also find a "kuru-kuru" factory - "circular" in Japanese - where bags and clothes are made from discarded clothing, and a kuru-kuru shop, where residents can drop off and pick up unwanted items. In fiscal year 2016, nearly 90 percent of the 15 tons of items brought in were taken by someone else.

Still, Kamikatsu is stuck. So is San Francisco. There are still too many items that aren't recyclable in the waste stream, like used diapers, to finally do away with all waste. "As a community, we can only do so much," Sakano said. "The businesses need to change their product design."

Is it enough to be proud of slashing the waste total? Yes: "We've already shown that we can do this," Sakano said.

But is it enough to stop? "Everyone needs to start," she said. "Otherwise we don't see the future."