Section 120(3) in The West Bengal Motor Vehicles Rules, 1989
(3)Etching of registration mark in cases of metered taxis. - [(i)] [Sub-rule (3) renumbered as clause (i) of that sub-rule vide Notification No. 4755-WT/3M-60/93 dated 28.05.1993.] In respect of every metered taxi or motor cab, the registration mark shall be distinctly and legibly etched on the top left hand corner of the front windscreen glass, on each of the window glasses and on the back windscreen glass. Such etching of registration mark in respect of metered taxis or motor cabs shall be a condition of the permit.(ii)[ Registration mark of metered taxi or motor cab shall also be etched on the back of the driver's seat.] [Clause (ii) inserted vide ibid.]