Which period shall be considered for interest under Section 234A if the return is not furnished and an updated return is filed?
​If the income-tax return is not furnished by the assessee and subsequently he files an updated return, interest shall be charged on the amount of self-assessment tax payable on the total income as declared in such updated return.

The interest shall be charged for the period commencing from the date immediately following the due date for filing the original return of income and ending with the date on which the updated return is furnished.​​