The Centre on Tuesday made it mandatory for international passengers arriving in India to pre-book RT-PCR test.
The international passengers arriving at six major Indian airports would be required to pre-book their tests.
"The 'Air Suvidha' portal would be modified to allow the passengers to pre-book their RT-PCR test if they are coming from the 'AT RISK' countries or have visited 'AT RISK' countries in the last 14 days," Ministry of Civil Aviation said in an office memorandum on Tuesday.
"Link to the concerned airport website would be provided on the Air Suvidha platform, which would be displayed to the passengers while they fill up the self-declaration form (SDF)," it added.
As per the memorandum, to stabilise the system and to ensure that the passengers do not face any problem in pre-booking, it may be implemented in six Metro cities, namely Delhi, Mumbai Kolkata, Chennai, Bengaluru and Hyderabad in the first phase.
"Considering the convenience of the travellers, a lead time of a week would be provided, i.e., for the new system to come into effect on December 20," the statement said.
"DGCA is requested to issue an advisory to all the airlines to check mandatory pre-booking of their passengers before they board the flight," he added.
The memorandum also said that in case any passenger is having any difficulty in pre-booking, he/she may not be denied boarding, but it would be the responsibility of the airlines to identify and accompany such passengers to the registration counter at the airport for testing.