Detailed guidelines for the issuance of flights tickets have been issued by the DGCA. These refunds are for the flights cancelled during the lockdown period. The guidelines were issued after the verdict of Supreme Court. As per the verdict, full and immediate refund must be given to all passengers for the flights cancelled between March 25 and May 24. It may also be noted that domestic flights did not operate in the country during this period. 

Based on the verdict, the DGCA created 3 categories of passengers for the refund purposes. 

1. Passenger who booked tickets during lockdown for travel during Iockdown i.e. from 25th Mar 2020 to 24th May 2020.
2. Passengers who booked tickets any time prior of lockdown but journey up to 24th May 2020 and cancelled due COVID-19.
3. Passengers who booked ticket anytime but for Journey after 24th May 2020.

As per this, passengers belonging to the 1st category must be given full refund by the airline concerned. The DGCA said that the airline must make all endeavours to refund the passngers in the 2nd category within 15 days. It also said that if any airline is under financial stress, they shall provide credit shell equal to the amount of fare collected. The shell can later be used by the passenger to book any ticket by March 2021. The passengers belonging to the third category shall be refunded in accordance with existing DGCA rules. 

Even for international travel, when the tickets have been booked on an Indian carrier and the booking is ex-India, if the tickets have been booked during the lockdown period for travel within the lockdown period, immediate refund shall be made.

-If the tickets are booked for international travel on a foreign carrier and the booking is ex-India during the lockdown period for travel within the lockdown period, full refund shall be given by the airlines and said amount shall be passed on immediately by the agent to the passengers, wherever such tickets are booked through agents. In all other cases airline shall refund the collected amount to the passenger within a period of three weeks.
-Scheduled domestic passenger flight services resumed in the country after a gap of two months on May 25. Scheduled international passenger flights continue to remain suspended in the country since March 23. However, special international passenger flights have been operating under the Vande Bharat mission since May and under air bubble arrangements formed with various countries since July.(information copied from source for authenticity)