Biodegradable bags are bags capable of being decomposed by bacteria or other living organisms. They are basically made of

Biodegradable bags are made mainly from starch, which microbes can break down.

Normal plastic is petroleum-based and resists decomposition.

Synthetic fibres are also non-degradable and unsuitable for such bags.

Petroleum itself is the raw material for conventional non-degradable plastic.

Starch from maize or potato forms films that decay into simple compounds.

Such bags compost far faster than polythene ones.