As the government says India has been able to prevent community transmission of the coronavirus, there are concerns about at least three different clusters of cases in Delhi, in which the primary source of the infection is unknown, an NDTV investigation has found.
Both the centre and Delhi government have stressed that the nationwide lockdown since the end of March staved off community transmission or the third stage of the spread of a virus, where the source of the infection is unclear.
At this stage, people who have had no travel history or who have not come in contact with any other known infected persons fall sick, making it harder to contain the spread of the disease.
In South Delhi, a portion of the Tughlakabad Extension area has been turned into a containment zone with over 50 infected.
The primary source, according to officials, was a 62-year-old grocery store owner who tested positive on April 13, and two of his friends who visited him. The friends mingled with others in the neighborhood, further spreading the virus.
Over the next two weeks, medical workers tested 200 contacts of this group of three and found 51 infected.
However, it is unclear how the grocery store owner was infected in the first place. The summary of the police report on him says, "At this stage, it would be wrong to suggest the source of COVID-19 infection to the patient."
"Till date we haven't been able to find the source of infection of our first patient. From him, the rest of them got infected. He is a shopkeeper and probably got something from a customer only," said Savita Saini, the Delhi government's medical officer in-charge of the area told NDTV.
Dr Saini added that there have been one or two other cases in the area, in which the source of infection is unknown.
Satish Rana, the officer in charge of Govindpuri police station, said the police had helped in contact tracing, but they still do not know how the store owner caught the virus.
In Jahangirpuri in North Delhi, a 55-year-old woman has been linked to a large cluster of infected persons.
The woman had become breathless and was first taken to a number of local hospitals in the area, including Babu Jagjivan Ram Hospital, Baba Saheb Ambedkar Hospital and then to RML Hospital, where she died on April 5.
Virender Singh, a Sub Divisional Magistrate, said her test result came four days after her death, on April 9, and it said she had the coronavirus; by then many had attended her funeral, unaware of her status.
At least 31 had been infected, including 26 of her relatives.
But here too, it is unclear how the woman, Jahangirpuri's patient zero, was infected.
"She did not have any travel history," said Mr Singh, directing further questions on the case to the district medical team.
In Kapashera in Southwest Delhi, 58 people in just one building were found infected over the past week. Officials here suspect that the source may have been a pregnant woman who lives in the building and was asymptomatic. The hospital where she goes for her regular pregnancy checkups tested her and found she was positive for the virus on April 19.
Officials refused to comment, but government sources said she had no travel history and the source of her infection was unknown. But they also added that the woman was a surrogate mother and used to visit several hospitals and fertility clinics. She could have possibly caught the infection there, they said.
Four positive cases have also been detected in the District Magistrate's office, just across the road from the building.
A total of 11 staff members including the District Magistrate are now under home quarantine as a precautionary measure, though they have tested negative in the first round. The source of infection is unknown in this case too.
A senior official in Delhi government, who works with the health department, said, "The current spread of the disease does not qualify to be called community spread as per experts."
On April 24, Union Health Minister Harsh Vardhan had said at a videoconference with state health ministers on coronavirus: "We are all worried if we are in Stage-3, but we have been able to save the country largely from going into Stage-3. We have all the information connected with clusters and hotspots."