18. Penalty for incomplete and untrue declaration, etc.- Whoever- (a) delivers in respect of a motor vehicle a declaration or additional declaration wherein the particulars required by or under this Act to be therein set forth are not fully and truly stated, or (b) obstructs any officer in the exercise of the powers conferred by clause (a) of section 17 or fails to stop the motor vehicle when required to do so by such officer under clause (b) of that section, shall on conviction be punishable- (i) with fine which may extend to a sum equal to the annual tax payable in respect of such vehicle; and (ii) in the event of such person having been previously convicted of an offence under this section, with fine which may extend to a sum equal to twice the annual tax payable in respect of such vehicle. | 
