There is a lot of controversy on what is compostable and what is biodegradable. For everyone's understanding, all compostable products are biodegradable but not all biodegradable products are compostable, meaning compostability is a phenomenon.
As for the standard as far the environment is concerned, it has to be in a controlled condition, with a controlled temperature, in the presence of microbes as well as in the presence of moisture.
When we talk about compostability, it has to happen either in an industrial facility or in a home composting facility. Saying a product is compostable has no meaning. It is a misnomer. We have to say whether it is at home or in industry.
Both have different conditions. For home, there is a one-year degradation time, and for industry, there is a six-month degradation time to carbon dioxide and water.