On 24 March, India shut its $2.9 trillion economy, closing its businesses and issuing strict stay-at-home orders to more than a billion people. Air, road and rail transport systems were suspended.

Now, more than two months after the first case of Covid-19 was detected in the country, more than 5,000 people have tested positive and some 150 people have died. As testing has ramped up, the true picture is emerging. The virus is beginning to spread through dense communities and new clusters of infection are being reported every day. Lifting the lockdown could easily risk triggering a fresh wave of infections.

A harsh lockdown is certain to slow down the disease. Virologists I spoke to believe India is still at an early stage of the infection. The country still doesn't have enough data on the transmissibility of the virus or even how many people could have been infected and recovered to develop adequate herd immunity. (It is slowly beginning finger prick blood tests to look at the presence of protective antibodies.)

More than 250 of India's 700-odd districts have reported the infection. Reports say at least seven states have a third of all infections, and want the lockdown extended. Six states have reported clusters of rapidly growing infections - from the capital Delhi in the north to Maharashtra in the west and Tamil Nadu in the south.

Economic fallout

Not surprisingly, the lockdown is already hurting the economy. Many of the early hotspots are economic growth engines and contribute heavily in revenues to the exchequer. Mumbai, India's financial capital and Maharashtra's main city, accounts for more than a third of overall tax collection. The densely populated city has reported more than 500 cases and 45 deaths, and numbers are steadily rising. Authorities say the infection is now spreading through the community. Mumbai has made wearing face masks mandatory.

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India has ramped up testing during the lockdown

Many of these hotspot clusters are also thriving manufacturing bases. The spread of infection means that they will be under lockdown for a longer period of time.

The services industry, which generates almost half of India's GDP, is also likely to remain shut for some more time. Construction, which employs a bulk of migrant workers, will remain similarly suspended. The unemployment rate may have already climbed to more than 20% after the lockdown, according to a report by the Center for Monitoring Indian Economy.

For the moment, economists say, the government will have to prioritise farming over everything else to ensure the livelihoods of millions and secure the country's future food supplies.

Half of India's labour force work on farms. The lockdown happened at a time when a bumper winter crop had to be harvested and sold, and the rain-fed summer crop had to be sowed. The immediate challenge is to harvest and market the first crop, and secure the second.

Moving trucks to pick up produce and take them to markets, with adequate social distancing and hand washing will be something the government will have to move on quickly.

"The immediate challenge is to ensure that rural India is not hit," says Rathin Ray, an economist. "Realistically, a complete lockdown cannot be continuously maintained beyond early May. We don't have a choice but to reopen gradually after that."

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India has been under a lockdown from 24 March

There is little doubt about that. For his part, SK Sarin, who heads a government advisory panel on combating the disease, says the lockdown can be only eased in a "graded manner in areas that are not hotspots" and that the hotspots remained cordoned off.

Like other affected countries, India will have to prepare itself for what Gabriel Leung, an infectious disease epidemiologist and dean of medicine at the University of Hong Kong, describes as several rounds of "suppress and lift" cycles.

During these periods "restrictions are applied and relaxed, applied again and relaxed again, in ways that can keep the pandemic under control but at an acceptable economic and social cost."

Also, Dr Leung observes, "how best to do that will vary by country, depending on its means, tolerance for disruption and its people's collective will. In all cases, however, the challenge essentially is a three-way tug of war between combating the disease, protecting the economy and keeping society at an even keel".

It is now clear that shutdowns need to continue until transmission has slowed down markedly, and testing and health infrastructure has been scaled up to manage the outbreak.

Experts from the southern state of Kerala, a striking outlier that is containing the infection thanks to a transparent government and a robust public health system, say it isn't time to lift the lockdown yet and have recommended a three-phase relaxation.

For most countries, easing the lockdown is a tricky policy choice. It sparks fears of triggering a fresh wave of infection and presents the inevitable trade-off between lives and livelihoods. French Prime Minister Edouard Phillipe, says relaxing the lockdown in his country is going to be "fearsomely complex". In a crisis like this, according to his Dutch counterpart Mark Rutte, leaders have to "make 100% of the decisions with 50% of the knowledge, and bear the consequences."

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 India's financial capital, Mumbai, is emerging as a hotspot

It is going to be tougher for India with its vast size, densely packed population and enfeebled public health system. Also, no country in the world possibly has so much inter-state migration of casual workers, who are the backbone of the services and construction industries.

How will India manage to return these workers to their work places - factories, farms, building sites, shops - without a substantial easing of public transport at a time when crowded trains and buses can be a vector of transmission and easily neutralise the gains of the lockdown? Even allowing restricted mobility - allowing social distancing, temperature checks and passenger hygiene - would put considerable pressure on the public transport system.

The policy choices are fiendishly tough, and the answers are far from easy. India bungled the lockdown by not anticipating the exodus of millions of migrant workers from cities. The weeks ahead will tell whether the fleeing men, women and children carried the infection to their villages. The country simply cannot afford to make similar mistakes again while trying to relax the lockdown. Nitin Pai of The Takshashila Institution, a think tank, believes states should be left to decide on easing restrictions, and decisions "should be based on threat [of infection], which should be determined by extensive testing".

This week Prime Minister Narendra Modi said that the "situation in the country is akin to a social emergency". His government now needs make sure that the looming threat to the nation's health and economic progress is tackled skilfully.