That's a great question! If you look around cities worldwide, you'll notice a pretty consistent color scheme for public trash cans. The most popular color by far is a dark green, often in a forest or hunter green shade. You'll also see a lot of gray or beige bins, especially the modern metal ones. For recycling, blue has become the almost universal standard.
So, why these colors? It's not about fashion, but pure function. Dark green and gray are chosen because they are excellent at hiding dirt and stains. A public bin gets messy, and these muted, earthy tones help it look reasonably clean for longer between collections, which is a big plus for city maintenance budgets. They also tend to blend into urban landscapes—parks, sidewalks, and streetscapes—without being too visually intrusive.
The rise of blue for recycling is a deliberate move for clear public communication. By consistently using blue for paper, plastic, and glass, cities create an instant, intuitive signal. You see a blue bin, and you think "recycling," even before reading the label. This simple color-coding makes waste separation easier for everyone.
You might occasionally spot other colors for specific purposes, like red for medical waste or yellow for certain types of industrial collection, but for the general street litter bin, green and gray remain the dependable, practical champions.