Canada plastic bag ban

The City of Montreal is banning thin plastic bags. The law was put in place on January 1st 2018, but merchants were given time until June 5th of the same year to actually follow it. After that harsh penalties would rain down on those ignoring it. Interestingly after the whole of Canada discussed this plan in 2016 only Montreal emerged as the only city enforcing it. I suppose not even her suburbs do, let alone other cities in Quebec.

But does this make sense? Of these bags, the conventional plastic bag banned in Montreal is the one that has the least impact in the category of disposable bags, while the thicker plastic bags and Paper bags ar always allowed, are overall more polluting.

Let's not forget food wrapped in plastic. Like bread, cookies. You might need one plastic bag to carry 5 to 10 articles usually wrapped in plastic from your grocery store. Thus a plastic bag ban only reduced the waste by about 10%. Many bags you take from the cashier are bio degradable. Suppose that means in the landfill they just degrade without harming the environment. If so, why ban them?