(4)A certificate granted under sub-section (3) shall remain in force till the expiry of the period specified therein or, if it is cancelled by the ] [Inserted by Act 19 of 1970, Section 24 (w.r.e.f. 1.4.1970).] [Assessing Officer] [ Substituted by Act 4 of 1988, Section 2, for " Income-tax Officer" (w.e.f. 1.4.1988).] [before the expiry of such period, till such cancellation.
