Image copyright PTI Image caption This city of five million people has been under a lockdown since last week

Around 05:00 local time (23:30 GMT) of 8 March, the intensive care unit of a private hospital in the northern Indian state of Rajasthan received a 52-year-old man suffering from pneumonia. He was also having problems breathing.

At the Brijesh Bangar Memorial Hospital in Bhilwara, the new patient was examined by 58-year-old Alok Mittal, a doctor of internal medicine, and his team. The patient wasn't asked about any travel history; nor did he disclose anything. There were six other patients in the ICU.

The man's condition did not improve much, and two days later, he was sent to a private hospital in Jaipur, some 250km (155 miles) away, for specialised treatment. In Jaipur, he was treated in two hospitals. "We had no idea what was in store," Shantilal Acharya, an intensive care nurse who received the patient in the Bhilwara hospital, told me.

For reasons that are still unclear, even the hospitals in Jaipur didn't test a patient with severe pneumonia for coronavirus. His condition deteriorated swiftly and he died a few days later, on 13 March. The news of his death was conveyed to Dr Mittal and his team.

Image copyright SHAUKAT AHMED Image caption The infection possibly spread from a private hospital in Bhilwara

Strangely enough, the doctors didn't appear to comprehend the gravity of the situation even though it was clear that India was facing an imminent outbreak of Covid-19. The country has reported more than 460 confirmed cases and nine deaths so far, and testing remains low. On 9 March, according to reports, Dr Mittal and a few others travelled to the city of Udaipur, put up in a resort and played Holi, the Indian spring festival of colours. (Repeated attempts at getting through to Dr Mittal by phone and text yielded no results.)

Days after the death of the pneumonia patient, Dr Mittal and a colleague checked themselves into an isolation ward of a government hospital. Over the next few days, a few more colleagues from the hospital joined them in isolation. Twelve of them, including Dr Mittal, tested positive for Covid-19.

As news of the infections leaked, all hell broke loose. The private hospital was popular with its residents, and many regularly visited its thriving out-patient department for treatment. As people panicked and began blaming the doctors for spreading the infection, authorities moved swiftly.

Image copyright SHAUKAT AHMED Image caption People have been stopped from entering or leaving Bhilwara

They imposed a "civil curfew", prohibiting people from coming out of their homes and banning public gatherings. They shut schools, colleges, offices, and stopped people from leaving or entering the district. The private hospital was sealed and its 88 patients moved to other healthcare facilities in the area. "Officials were telling us the threat was serious and there was a chance of an outbreak," local journalist Pramod Tiwari told me.

So Bhilwara, fearing a serious outbreak, did everything that India did a few days later. So could this city of 400,000 people and a major textile making hub, turn out to be India's first coronavirus "hotspot"?

Consider this.

Of the 69 people tested in the city until Sunday evening, 13 people - including doctors and paramedics - aged between 24 and 58, have tested positive. They include three doctors and nine health workers. Thirty-one people - mostly hospital workers - are in isolation. "Most of them are doing fine," Dr Arun Gaur, the chief medical officer of the district, told me.

But things could get really bad.

Between 20 February and before going into isolation last week, Dr Mittal and his team of doctors at the hospital saw 6,192 patients who came from 13 districts of Rajasthan and 39 patients belonging to four other states. Drawing from the experience in China and Italy, doctors now know that hospitals might turn out to be the "main source" of Covid-19 transmission. Also, both MERS and SARS had high transmission rates within hospitals. The potential for community transmission of the infection across a large geographical area from the Bhilwara hospital is real, officials fear.

Image copyright SHAUKAT AHMED Image caption The city's borders have been sealed

So did the virus reach this city through the patient who was treated at three hospitals and went untested before he died? Or did one of the more than 80 patients admitted in the hospital transmit it? Or was it spread by another patient in the intensive care? Or had one of the doctors picked up the infection separately and spread it unknowingly?

Nobody will know until all the contact tracing and testing is complete, and that's the scary part.

The lack of early credible information on the transmission meant that rumours had a field day. Local media reported that one of the infected doctors had received guests from Saudi Arabia at home and had contracted the infection. He had then gone to the hospital and spread the infection to co-workers, the reports added.

Dr Niyaz Khan had to record a mobile phone video from his intensive care bed to squelch the rumour. With monitors beeping around him, Dr Khan, masked and breathless, implored: "Just to set the record straight, I have no relative in Saudi Arabia. I have a son and a wife. None of them is positive. Please don't believe what is coming in the media."

Another doctor said it was unfair to blame the hospital: "The patient fooled us and told us he didn't travel outside the country for the two days he was in the ICU with us." And Dr Mittal himself - his wife has also tested positive - recorded videos in isolation saying that he had tested positive, and he was doing well. "Please do not panic," the well-known doctor said.

Image copyright Getty Images Image caption Residents in the city have begun panicking

That is easier said than done.

Realising the gravity of the situation, 300 teams of government workers and volunteers have fanned out in Bhilwara city. They are knocking on the doors of some 78,000 houses, and asking residents whether they've had a guest from outside the country, been treated in the hospital or know anyone who has tested positive. The survey began on 18 March and will finish on 25 March. "They are asking if we have cold, cough and fever and telling us if we have any of the symptoms we should report for tests at the government hospital," a resident told me.

Another 1,900 similar teams have travelled out into neighbouring villages where more than 2.5 million people live. People in homes with suspect cases are being put into quarantine. Seven thousand people have been put into home quarantine so far.

Fearing a surge in infections, 20 more beds are being added to the hospital's 30-bed isolation ward, which is already full. Six private hospitals have promised to provide an additional 35 beds for isolation. Thirteen places with 450 beds - extendable to 2,000 beds - where people can be quarantined have also been identified, Rajendra Bhatt, the senior-most official of the district told me. "It's like fighting a war, but we have been agile and alert," he said.

Meanwhile the residents, like elsewhere in India, are enduring an extended lockdown and curfew. Rajkumar Jain, a professor of computer science, is locked down with 14 members of his joint family in a two-storey home. "We are in complete panic," he told me. "People are saying here that Bhilwara is going to become India's Italy."