Limitation period extension preserves authority to issue show cause notices and allows delayed refund claims after pandemic exclusion. Extension of the statutory limitation for issuance of show cause notices and recovery orders is directed for specified tax periods, with a pandemic-affected interval excluded from computation of limitation for both issuance of orders relating to recovery of erroneous refunds and for filing statutory refund applications; the measure is made effective from the commencement of the excluded interval under the administrative power to extend limitation.