Penalty for failure to pay tax.

If the tax due in respect of any motor vehicle has not been paid as specified in section 4, the registered owner or the person having the possession or control thereof shall, in addition to payment of the tax due, be liable to a penalty, which may extend to twice the quarterly tax in respect of that vehicle, to be levied by such officer, by order in writing and in such manner as may be prescribed: Provided that if the lumpsum tax under this Act has not been paid, the registered owner or the person having possession or control thereof shall, in addition to payment of the tax due, be liable to penalty which may extend to twice the lumpsum tax payable under clause (aa) of sub-section (1) of section 4.