You have to pay for polythene shopping bags at Keells?

Bought a few items at Keells today and the lady asked if I wanted a bag for it (too many small items, couldn’t have just carried it), I said yes and she said they charge for bags now.

Medium sized polythene bag for Rs 3.

I do understand how important it is to reduce the usage, but is this right? How is one supposed to just carry everything?