What is the difference between compostable and biodegradable plastics?
Compostable plastics are defined by measurable standards: under industrial composting conditions they must disintegrate within about 12 weeks and biodegrade almost completely within six months, leaving no toxic residue. Biodegradable simply means a material will eventually break down through microbial action, with no defined timeframe, environment, or endpoint. All compostable plastics are biodegradable, but not all biodegradable plastics are compostable.
This distinction is the single most important thing a packaging buyer can understand. A label that only says biodegradable makes no promise about how long degradation takes or what conditions are required. It could take months or many years, and it may leave fragments behind.
Why does biodegradable have no fixed timeframe?
The word biodegradable describes a general capability rather than a verified performance level. Almost any organic material biodegrades given enough time, so the term on its own tells you very little. Without a referenced standard such as IS 17088 or a testing body confirming the claim, biodegradable is effectively unregulated marketing language.
This is why some so-called biodegradable plastics are really conventional polyethylene blended with an additive that helps it fragment faster. Fragmentation is not the same as biodegradation. Breaking into smaller pieces can simply create microplastics that persist in soil and water.
How are compostable plastics defined by standards?
Compostable plastics are held to a specification. IS 17088 and comparable standards require the material to disintegrate physically, biodegrade into carbon dioxide, water and biomass, and pass ecotoxicity checks so the resulting compost supports plant growth. Each of these is tested under controlled industrial composting conditions, typically around 55 to 60 degrees Celsius with managed moisture and microbial activity.
Because the criteria are measurable, a certified compostable product carries a defensible, third-party-backed claim. That is the difference between a marketing adjective and a verified property.
Where do compostable plastics actually break down?
Certified compostable plastics are designed for industrial composting, not landfills or open littering. In a landfill, oxygen and heat are limited, so biodegradation is slow and unpredictable. Left as litter in soil or water, compostable plastics also do not reliably break down, because the temperature and microbial conditions they need are absent.
This means end-of-life infrastructure matters. Choosing compostable material only delivers its environmental benefit if the item is routed to composting rather than dumped. Buyers should plan disposal alongside procurement, not as an afterthought.
Which one should a buyer specify?
For most packaging and single-use applications, specify certified compostable material and reference the standard it meets. A standards-defined claim protects you from greenwashing exposure and gives customers a clear disposal instruction. Avoid vague biodegradable claims that no test can support.
At Anjaneya Bio Products we manufacture compostable granules, films and bags built to CPCB criteria, so the end-of-life behaviour is documented rather than assumed. The information here is meant to help you ask the right questions of any supplier, including us.
Key takeaway
Compostable is a standards-defined claim: certified material disintegrates within about 12 weeks and biodegrades within six months under industrial composting. Biodegradable has no defined timeframe or endpoint and can be misleading on its own.