2. Red represents harmful substances, which are sometimes marked with orange. Harmful substances include waste batteries, fluorescent tubes, paints, expired drugs, cosmetics and other substances that are not recyclable and have certain pollution hazards.
3. green: in the case of a variety of plastic trash cans, green represents kitchen waste, which can be used as fertilizer for plant nutrients, and can be decomposed and absorbed by natural microorganisms and plants after being buried, thus playing a role in recycling waste.
4. Blue: it represents recyclable garbage, including materials with use value such as plastics, paper and metals, which will be incorporated into the waste recycling system for resource recycling.
5. Gray: garbage other than harmful substances and recyclable substances, bricks, ceramics, muck and other wastes that are difficult to recycle, which are generally incinerated and buried.