THE GARBAGE glut is essentially a phenomenon of packaging. According to a recent report by the Washington-based Worldwatch Institute, packaging accounts for about 30 percent of the weight and 50 percent of the volume of household waste.

The average American discards 660 pounds of packaging every year. Half of that is paper, from junk mail to cereal boxes, followed by glass, metals and plastic. But plastic is gaining fast on the glass bottle and tin can. In the last decade, the plastics component of municipal waste has nearly doubled, to between 6 and 8 percent.

Americans also are the world's most prolific generators of rubbish. The average New Yorker pitches nearly four pounds of trash a day, or nearly three-quarters of a ton every year. Toyko isn't far behind, at nearly three pounds a day.

Not surprisingly, less-developed nations generate far less trash, largely because their economies cannot support the consumption practices that result in soaring piles of garbage. Pre-packaged convenience foods are a relative rarity in Calcutta, where the rubbish rate runs at slightly over a pound a day per person.

But less-developed nations, where scavenging remains a tradition, may have an advantage over the industrial world when it comes to recycling.

The Worldwatch Institute's Cynthia Pollock reports that in Cairo, for example, a group of former oasis dwellers known as the zabaleen collect more trash than the city's sanitation department. The zabaleen sort the trash, feeding organic materials to their pigs and selling much of the rest for recycling.

Private investors have recently taken an interest in the century-old system and have provided such processing facilities as plastic granulation machines and a composting plant.

In Bangkok and Manila, municipal collection crews supplement their salaries by sorting and selling paper, bottles, cans and plastics picked up on their routes. It's lucrative enough that in Manila, sanitation crews bring along an unpaid member to do the sorting.