That's an excellent and practical question! The short answer is: while there is no single, globally enforced standard, strong common practices and regional standards have created a high degree of consistency, especially in public urban spaces.
In many parts of the world, particularly in North America and Europe, you'll most often find:
* Blue Bins for Recycling: Blue has become the dominant color for containers meant for recyclables like paper, plastic, metal, and glass. This is a widely recognized convention.
* Black or Gray Bins for General Trash: Black or dark gray is commonly used for non-recyclable, landfill-bound waste. The contrast with blue helps quick visual identification.
* Green Bins for Organics: In cities with composting programs, green bins are frequently designated for food scraps and yard waste.
However, it's crucial to check locally. Colors can vary. For instance, some areas use green for recycling or have different systems altogether. The key is to look for the labels or symbols on the bin, which are more important than color alone. Standardizing colors, even informally, reduces public confusion, increases proper sorting, and makes waste management systems more efficient. So, while you can often rely on "blue for recycling," always verify with the posted instructions to be sure.