9. Assessment of escaped tax.-

(1) If for any reason any tax payable under this Act has escaped assessment or has been assessed at a rate lower than the rate at which it is assessable the assessing authority may at any time within four years from the end of the year to which the tax relates, proceed to assess or reassess the tax, as the case may be, to the best of its judgement after issuing a notice to the employer or the person concerned and after making such enquiry as it considers necessary:

 Provided that the tax shall be charged at the rate at which it would have been charged if such tax had not escaped assessment or, as the case may be, had not been assessed at a rate lower than the rate at which it was assessable.

(2) In making an assessment under sub-section (1), the assessing authority, if it is satisfied that the escape from assessment was due to wilful non-disclosure of information or attempt at evading the tax by the employer or the person direct such employer or the person to pay, in addition to the tax assessed under sub-section (1), a penalty not exceeding one and half times the tax so assessed :

Provided that no penalty under this sub-section shall be imposed unless the employer or the person affected has had a reasonable opportunity of showing cause against such imposition.