Power to recover penalty where tax not paid within time

Where any person fails to pay within such time as may be fixed by rules under this Act any amount due from him on account of the tax assessed on him under this Act, the assessing authority may recover from such person the penalty in addition to the tax so assessed: Provided that no such penalty shall be recovered from such person without affording a reasonable opportunity to him and unless the assessing authority is satisfied that he has wilfully failed to pay the tax.