because they are plastic shopping bags are increasingly recyclable or biodegradable .Traditional plastic bags are usually made from polyethylene, which consists of long chains of ethylene monomers. Ethylene is derived from natural gas and petroleum. The polyethylene used in most plastic shopping bags is either low-density (resin identification code or, more often, high-density (resin identification code.Color concentrates and other additives are often used to add tint to the plastic. Plastic shopping bags are commonly manufactured by blown film extrusion.
In my opinion the word reason here is RENEWABILITY/SUSTAINABILITY.
Explanation: Renewability and Sustainability are both synonyms and can be defined as the ability for something to be produced or sustained for a long period of time without damaging the environment or without depleting a resource. Modern plastic shopping bags are increasingly recyclable or biodegradable. modern bags are made of vegetable-based bioplastics, which can decay organically and prevent a build-up of toxic plastic bags in landfills and the natural environment.
