GSTR-3B filing deadlines set with staggered due dates and mandatory ledger-based payment by the return due date. Requires electronic filing of FORM GSTR-3B for April-September 2020 through the common portal with generally applicable monthly due dates, and provides staggered later due dates for small taxpayers in specified groups of states and union territories. Tax liabilities must be discharged by debiting the electronic cash or electronic credit ledger as applicable, and interest, penalty, fees or other amounts by debiting the electronic cash ledger, not later than the prescribed last date for furnishing the return.