[multiplegeorges]

The first country/company to develop properly biodegradable plastics with similar properties to existing ones will be very rich.

But the market won't create that solution unless regulations create the problem to be solved: no more single-use non-biodegradable plastics.

[tomp]

Taxation (or in this case, just internalizing the negative externalities) is almost always the better solution than outright bans.