Section 153(2) in The West Bengal Motor Vehicles Rules, 1989
(2)Upon receipt of an application under sub-rule (1) the Regional Transport Authority may, in its discretion, reject the application -(i)if it has, previous to the application, given reasonable notice of its intention to reduce the number of transport vehicles of that class generally or in respect of the route or area to which the permit applies; or(ii)if the new vehicle differs in material respects from the old one; or(iii)if the holder of the permit has contravened any of the provisions thereof; or(iv)if the Government notifies its intention to nationalise the route or area.