GSTR-3B return deadline: monthly returns due by the twentieth day succeeding the month; tax payable via electronic ledgers. The notification prescribes that FORM GSTR 3B for each month from October 2019 to March 2020 must be furnished electronically through the common portal on or before the twentieth day of the succeeding month, and requires every registered person to discharge tax, interest, penalty, fees or any other amount payable under the Act by debiting the electronic cash ledger or electronic credit ledger, as applicable, not later than that prescribed due date, subject to the provisions of section 49 of the Act.