Manufacturers of plastic below 50 microns will face instant arrest and citizens carrying the thin polythene will be fined up to Rs100, under a new set of restrictions proposed by the Brihanmumbai Municipal Corporation. Another proposal is to widen the range of banned plastics with the least permissible size raised from 50 microns to 70. Recently, the Maharashtra Pollution Control Board has shut down four units for producing plastic below 50 microns.