Payment window for overdue tax permits notified persons to settle unpaid tax, surcharge and penalty with interest for delay. The amendment to section 187(1) empowers the Central Government to notify classes of persons who may pay unpaid tax, surcharge and penalty on or before a notified date, subject to interest for the delay computed for each month or part of a month from the day after the due date until payment; the proviso is deemed effective from 1 June 2016.