Section 240(2) in The West Bengal Motor Vehicles Rules, 1989
(2)Save in the case of the uncovered top deck of a double-decked vehicle, every public service vehicle shall have suitable windows, venetians or screens capable at all times of protecting the passengers from the weather with-out preventing adequate ventilation of the vehicle. When the screens are made of fabric, the whole of them shall at all time be fastened securely to the vehicle.
