Paytm, in a statement, said the coronavirus-infected staffer has recently returned from Italy, the worst-hit nation in Europe. The company has advised its employees to work from home for the next two days, the statement added.

Fourteen of the 16 infected Italian tourists are quarantined in Delhi. They were a part of a group of 23 Italians, which traveled to Rajasthan last month. One of them - currently in Jaipur - tested positive on Tuesday; his wife has also tested positive. This is the biggest group in the country to be infected with coronavirus.

All passengers of international flights will have to undergo screening, and not just from the 12 countries listed earlier, Union Health Minister Harsh Vardhan said. Over 5,89,000 people have been screened at 21 airports in two months, over 10 lakh screened at borders with Nepal and around 27,000 are under community surveillance, he added.

India has now stepped up preventative measures including barring visitors from Italy, Iran, South Korea and Japan, except diplomats and officials from international bodies. The Union Health Ministry has advised people not to travel to China, Iran, South Korea and Italy. It has also asked all citizens to avoid non-essential travel to other affected nations.

The Union health ministry has issued an advisory for schools, asking that large gatherings be avoided. Anyone -- staff or student -- who has travelled to a COVID-19 country in the last 28 days should be home quarantined for 14 days, the advisory said. Also, anyone with symptoms should be reported and should not return without doctors' advise.

Of the total 28 coronavirus cases in India, one is a 45-year-old man from Delhi, who also visited Italy. Six others infected are among his friends and family. A Bengaluru-based techie in Hyderabad had tested positive on Monday. First three coronavirus patients in the country from Kerala, who contracted infection in January, have been cured.

Prime Minister Narendra Modi tweeted on Wednesday that he would not participate in any Holi events this year. "Experts across the world have advised to reduce mass gatherings to avoid the spread of COVID-19 Novel Coronavirus. Hence, this year, I have decided not to participate in any Holi Milan programme," he wrote. Union Home Minister Amit Shah also tweeted an appeal to "everyone to avoid public gatherings" and said that he, too, would not participate in any Holi events.

On Tuesday, PM Modi had said that he had held "an extensive review regarding preparedness on the COVID-19 Novel Coronavirus" and "there is no need to panic". Delhi Chief Minister Arvind Kejriwal also assured the people in the national capital about the arrangements, urging them not to panic.

Hundreds of Indians, including fishermen and students, are stranded in Iran where coronavirus is spreading fast and nearly 1,000 are infected. The government on Wednesday said that if the Iranian government lent its support, a testing facility could be set up there to help bring back the Indians.