Judgment

DUTT, J. :- The appellants, who are all registered firms within the meaning of S. 2(39), Income-tax Act, 1961, hereinafter referred to as the Act, have preferred these appeals against the judgments of the Gauhati High Court overruling the challenge of the appellants as to the legality of the interest charged by the Income-tax Officer for the delayed filing of returns and also as to the constitutional validity of sub-s. (4) of S. 139 of the Act, as it stood before April 1, 1971.

2. The relevant provisions of S. 139, as it stood prior to April 1, 1971, are as follows : -

"S. 139(1). Every person, if his total income ......... during the previous year exceeded the maximum amount which is not chargeable to income-tax, shall furnish a return of his income ...................

(a) in the case of every person .............. before the expiry of six months from the end of the previous year................, or before the 30th day of June of the assessment year, whichever is later;

(b) in the case of every other person, before the 30th day of June of the assessment year :

Provided that, on an application made in the prescribed manner, the Income-tax Officer may, in his discretion, extend t