MUMBAI (BLOOMBERG) - At midnight on April 17, as a deadly new wave of the coronavirus overwhelmed India, Mumbai's Municipal Commissioner Iqbal Singh Chahal learned that six hospitals in his city would run out of oxygen within hours - putting the lives of 168 patients at risk.

Amid the ensuing scramble, the patients were rushed to the temporary hospitals Mr Chahal's team had set up during the city's first wave in 2020. He hadn't dismantled the facilities even when cases dipped. Unlike most Indian hospitals that relied on cylinders, they had been equipped with pipes that supplied oxygen directly to patients' beds. All 168 survived.

That night - which Mr Chahal describes as the scariest he's ever had - offers a look at tactics India's financial capital used to quell its outbreak faster, and with fewer casualties, than other parts of the country.

Mumbai has reported 2,784 deaths since the second wave began on March 1, around a fourth of the 10,595 in capital New Delhi. Even India's Supreme Court has suggested that aspects of Mumbai's model could be adopted in other parts of the nation like New Delhi.

By contrast, the record number of daily deaths India continues to report, along with the collapse of the health system in parts of the country, have highlighted broad shortfalls in governance and public planning nationally. The country reported an unprecedented 4,529 deaths on Wednesday (May 19).

Mr Chahal attributes the city's successes partly to a decentralised system his team set up during the first wave, which included neighbourhood war rooms to manage cases by locality.

He's also made vast changes to the way the city sourced and used its medical oxygen, creating emergency stocks and tracking systems for tankers. So, even as families around India desperately pleaded for supplies on social media, Mumbai's patients reported fewer problems.

With a population of 16 million spread across glistening skyscrapers, apartment complexes and sprawling slums, Mumbai is the world's second-most densely packed city, according to data from the United Nations. About 32,000 people are crammed in per square kilometre. That makes lessons from India's financial capital particularly valuable as fears grow about outbreaks in other crowded places from Bangkok to Kathmandu.

"I knew it was a long drawn war; and I knew only systems can win the wars - individuals can't," Mr Chahal said in an interview via Zoom. "Devising systems and making them run on auto pilot is key to the Mumbai model."

As of May 11, Mumbai had almost half the number of active virus cases as capital New Delhi. Delhi Health Minister Satyendar Jain and Principal Secretary of Health Ashish Chandra Verma didn't reply to calls seeking comment.

Still, the risks to Mumbai are far from over. The city has recorded 688,696 cases since the pandemic began, adding 1,544 on May 16.

Mr Chahal is preparing for a third wave by setting up jumbo paediatric hospitals because public health experts have warned his team that more children might be infected in the next surge.

Managing the trajectory of the virus in Mumbai is crucial given the potential human toll of a runaway epidemic. And as India's financial capital, the city is also central to the nation's already battered economy.

Mumbai houses the nation's main stock exchange. It's where large multinationals like Unilever and global financial giants from Citigroup to KKR & Co have their Indian headquarters. It's home to the nation's central bank and India's mammoth film industry - Bollywood.

Mr Chahal, 55, says he built up administrative skills growing up in a military family: His father was an officer in the Indian army. Over the past decades, he's held a string of bureaucratic positions, including working on a proposal to remodel Dharavi and helming an overhaul of Maharashtra state's irrigation systems.

He had to hit the ground running last May, when Maharashtra's Chief Minister Uddhav Thackeray asked him to head the municipal corporation at the height of Mumbai's first wave. Bodies were piling up in mortuaries and the city's densest slum, Dharavi, was battling a fast growing coronavirus crisis.

Lessons from last year taught him the importance of a local approach and getting patients quickly isolated, a model he calls "Chase the Virus".

His team went door to door in Dharavi looking for people with symptoms and eventually isolating 150,000 people from the slum, a move that stopped the chain of infection. At the time, Mr Chahal also abolished the central hub handling the city's crisis and created local war rooms in each of the 24 administrative divisions - wards or neighbourhoods - of the city.

That localised approach helped as affluent neighbourhoods were worse hit during the second wave. The local war rooms got test reports and reduced the spread the of infection by pointing patients to the nearest available hospital beds. The city administration negotiated with private hospitals to allocate beds for Covid-19 patients at government decided rates.

"We set up an excellent public private partnership between hospitals which is still today not visible in rest of the country," Mr Chahal said.

When oxygen was running out during the second wave, Mr Chahal started to source oxygen from nearby states. Mumbai's civic authorities also banned hospitals from adding beds beyond their oxygen storage capacity, dodging the shortages that rocked other cities.

Vaccinations "Wiser after our experience of last year, when the second wave hit with its dangerous mutations, the Brihanmumbai Municipal Corporation quickly scaled up its infrastructure including beds, equipment and doctors," said Dr Hetal Marfatia, professor and head of the ear, nose and throat department at Mumbai's KEM Hospital. This time round most hospital beds had readily available oxygen lines, she said.

At times, Mr Chahal said he's had to simply find innovative ways to use limited resources. When ambulances were in short supply, he called the city's election commission and converted the 800 cars they sent over into ambulances by putting up partitions between the driver and passenger.

Still, Mumbai has been the epicentre of the virus twice, and local doctors warn of the continued risks. Mr Chahal's team has also drawn criticism for what some have described as a chaotic approach to vaccinations.

"Though our cases graph has come down now, I would say this is not the end," said Dr Vikas Oswal, a pulmonologist practising in clinics in Dharavi and other parts of Mumbai. "We are expecting a rise in cases within two weeks now, as vaccination centres are over flooded. They are not being managed properly."

Mr Chahal acknowledges some of the risks, saying he's preparing more jumbo hospitals with 6,500 added beds, and he's attempting to directly import vaccines from international companies.

Mumbai has received three bids to import Russia's Sputnik vaccines, he told Bloomberg TV in an interview Wednesday, adding that the city will reduce its positivity rate to 2 per cent by the end of May.

More than 20 per cent of India's tests are yielding positive results, far higher than the less-than-5 per cent the World Health Organisation considers as an indicator that the epidemic is under control.

"(The) more we vaccinate, the greater are chances that we reduce the threat of the next wave," Mr Chahal said.