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With India's success in ensuring a steady decline in infections after elections and festivals in November, many states - Karnataka, Maharashtra and Rajasthan - have started imposing night travel restrictions for Christmas and New Year's Eve.
The restrictions also being seen as an effort to check the spread of a new, more viral strain of the novel coronavirus firsts detected in UK in September. It has now been detected in many countries including Netherlands, Denmark, Belgium and even Australia.
The strain has not been detected in India as yet. But, state administrations in the country - among a host of nations that have suspended flight operations with Britain - are working round the clock to trace people who returned from UK in the last 4 weeks, and test them for COVID-19.
At least 22 people who came to India from the UK in the past few days have tested positive. Eleven people who came from or via the UK have tested positive in Delhi, eight in Amritsar, two in Kolkata and one in Chennai, authorities said.
Samples of those who tested positive have been sent to specialised labs like the National Institute of Virology in Pune to determine if the infection is from the mutant coronavirus.
Besides the virus mutation from Britain, another "potentially more infectious variant" of the novel coronavirus that causes COVID-19 has been found in the country in cases linked to South Africa, British Health Secretary Matt Hancock said.
"This new variant is highly concerning, because it is yet more transmissible, and it appears to have mutated further than the new variant has been discovered in the UK," he said, adding that immediate restrictions have been being imposed on travel from South Africa.
Susan Hopkins from Public Health England said she was confidence that the spread of the South Africa-linked variant would be controlled and said vaccines that have already been developed should be effective.
In the Unites States, more than 10 lakh people have received their first dose of a Covid vaccine. It is the world's hardest-hit country - 1.8 crore cases - where more than 3,20,000 people have succumbed to the virus, and it will likely be the leading cause of death in 2020 behind heart disease and cancer.
The virus, which has crippled life globally for more than a year, has reached the "end of the world" - Antarctica, where at least 36 people tested positive at Chile's Bernardo O'Higgins military base.
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