Countries in Europe, including the UK, and South Africa, Brazil, Botswana, China, Ghana, Mauritius, New Zealand, Zimbabwe, Hong Kong, Singapore, Tanzania and Israel have been placed in the "at-risk" category, the Aviation Ministry noted.
Delhi had reported its first case of the Omicron variant of the coronavirus on Sunday with a 37-year-old fully vaccinated man, who arrived in Delhi from Tanzania, testing positive.
The patient, a resident of Ranchi, had travelled from Tanzania to Doha and from there to Delhi on a Qatar Airways flight on December 2. He stayed in Johannesburg, South Africa, for a week. The person has mild symptoms.
According to the Union Health Ministry's guidelines that came into force from December 1 following the emergence of the Omicron variant, all passengers coming from "at-risk" countries have to compulsorily undergo RT-PCR test and two per cent of passengers arriving from other countries would have to take the test on a random basis.
The passengers will have to wait for the results before leaving the airport or taking a connecting flight, according to the guidelines.
 "Passengers arriving from Singapore on December 2 wait for their transport at the Delhi airport that has stepped up monitoring for Covid-19 after the Omicron variant of the virus was first detected in South Africa. (PTI Photo/Arun Sharma)")
