The Act has inserted the following sub section in section 34 of the Indian Income tax Act : " (I A) If, in the case of any assessee, the Income. tax Officer has reason to believe (i)that income, profits or gains chargeable to income tax have escaped assessment for any year in respect of which the relevant previous year falls wholly or partly within the period beginning on the 1st day of September, 1939, and ending on the 31st day of March, 1946; and (ii)that the income, profits or gain which have so escaped assessment for any such year or years amount or are likely to amount to one lakh of rupees or more; he may, notwithstanding that the period of eight years or, as the case may be, four years specified in subsection (1) has expired in respect thereof, serve on the assessee a notice containing all or any of the requirements which may be included in a notice under sub section (2) of section 22, and may proceed to assess or reassess the income, profits or gains of the assessee for all or any of the years referred to in clause (1) and thereupon the provisions of this Act shall, so far as may be, apply accordingly It was argued in Mohta 's case as well as in these petitions that the classification made in section 5(1) of 797 the impugned Act was bad because the word "substantial" used therein was a word which had no fixed meaning and was an unsatisfactory medium for carrying the idea of some ascertainable proportion of the whole, and thus the classification being vague and uncertain, did not save the enactment from the mischief of article 14 of the Constitution.