The materials which gets decomposed through natural processes, such as by the action of microorganisms are called biodegradable materials. For example, peels of vegetables and fruits, cotton clothes, wood and paper are biodegradable substances. These materials are easily decomposed by microorganisms. Temperature and sunlight may also play roles in the decomposition of biodegradable plastics and other materials.

The materials which are not easily decomposed by natural processes are called non- biodegradable materials. For example, tin, aluminium and other metal cans and plastics are non-biodegradable materials. Plastics can take several years to decompose. These materials are not environmental friendly and cause environmental pollution.