Biodegradable

Biodegradable plastic
A subset of them are compostable, which means that not only are they broken down by microbes, but they can be turned – alongside food and other organic waste – into compost. Only a minority of these plastics are home compostable, so, the label “compostable” most often means industrially compostable. That coffee cup with a Seedling logo you’re drinking from won’t decompose very quickly, if at all, on your home compost heap, but will break down inside the right kind of industrial equipment.
There’s a European standard for compostable packaging: EN 13432. It requires that the packaging break down under industrial-scale composting conditions within 12 weeks, leaving no more than 10% of the original material in pieces bigger than 2mm, and doing no harm to the soil itself through heavy metals or worsening its structure.--- By Kelly Oakes5th November 2019BBC.comWater soluble plastic
"A biodegradable material that engineers claim dissolves 100% upon contact with water is unveiled at a technology summit in Chile (Credit: Claudio Reyes/AFP/Getty Images)". [BBC.com, editor app wouldn't allow me to reuse the reference.]