Section 11A(2) in The Punjab Motor Vehicles Taxation Act, 1924
(2)If the amount of tax under Section 3 or Section 3-F or penalty under Section 8 due from an owner is not paid by him within the period specified in the prescribed notice, or, if no period is specified in the notice, within thirty days from the service of such notice, the owner shall in addition to the amount of tax or penalty, be liable to pay simple interest on the due amount of tax or penalty, as the case may be, at the rate of one and a half percent per month from the date following the date on which the period specified in the aforesaid notice or the period of thirty days, as the case may be, expires till the default continues :Provided that where the recovery of any tax or penalty is stayed by an order of a court, the amount of tax or penalty shall, after the order of stay is vacated, be recoverable along with interest at the aforesaid rate on the amount due and such interest shall be payable from the date, the tax or penalty had first become due.