What are compostable biodegradable plastics?

Degradable Plastics Committee: Composting is an aerobic treatment method to produce compost. Compostable refers to the ability of materials to be biodegraded during the composting process. A material including paper, plastic, etc., if claimed to be compostable, it must be stated that the material is biodegradable and disintegrates in the composting system (as shown in standard test methods) and is fully biodegradable in the compost end use . Compost must meet relevant quality standards. Quality criteria such as low heavy metal content, no biological toxicity, no clearly distinguishable residues.