Satish Chandra, C.J.

1. THIS is a consolidated reference for three assessment years, namely, 1961-62, 1962-63 and 1963-64. The question of law referred for our opinion is whether the Explanation added to Section 271(1)(c) of the I.T. Act, 1961, with effect from 1st April, 1964, was applicable to penalty proceedings for the aforesaid three assessment years, even though the return for each of these years was filed after 1st April, 1964.

2. THE assessee is a registered firm. It runs a steel rolling mill at Kanpur. For the assessment year 1961-62, the assessee filed its return on the 24th August, 1961. It filed a revised return on the 13th September, 1961. THE assessment was completed by the order dated 14th September, 1961. Assessments for the assessment years 1962-63 and 1963-64 were completed on the 19th February, 1963, and the 24th December, 1963, respectively, under Section 143(3) of the Act. It is thus evident that the returns were filed prior to the date of the assessment orders. In other words, the returns of income for all these three assessment years were filed long before the 1st April, 1964, when Section 271(1)(c) was amended and an Explanation added to Clause (c) of