Later, a man from Maharashtra who travelled to Mumbai from South Africa via Dubai and Delhi was found positive for the new variant too.
Delhi reported its first and the country's fifth Omicron case on Sunday morning. The patient, a Tanzania returnee, has mild symptoms as he had taken both doses of the vaccine.
A new variant of Covid-19 was first reported to the World Health Organisation (WHO) from South Africa on 25 November. As per the WHO, the first known confirmed B.1.1.529 infection was from a specimen collected on 9 November this year.
On 26 November, the WHO named the new Covid-19 variant B.1.1.529 as 'Omicron'. The WHO has classified Omicron as a 'variant of concern'.
To deal with this, several countries have imposed travel restrictions and local lockdowns.
India has added several countries to the “at-risk" list from where travellers would need to follow additional measures on arrival in the country, including post-arrival testing for infection.
According to the Centre, the countries designated as "at-risk" include the UK, South Africa, Brazil, Botswana, China, Mauritius, New Zealand, Zimbabwe, Singapore, Hong Kong and Israel.