CNN  — 

In February, it seemed like India had gotten Covid-19 under control, with daily cases falling nearly 90% from the peak of the first wave last year.

Now, the country is experiencing the world’s worst outbreak, with new cases surging past 400,000 per day and breaking the record for the highest single-day figure globally.

On the ground, these numbers translate to heart-wrenching tragedy. Photos show grieving families dressed in full protective suits at mass cremations, performing last rites surrounded by dozens of other burning funeral pyres. Hospitals have run out of basic medical supplies, with many patients dying due to oxygen shortages. Family members are driving from clinic to clinic, frantically searching for open ICU beds for their loved ones.

A man performs the last rites of a relative who died of Covid-19, as other funeral pyres are seen burning during a mass cremation in New Delhi, India, on April 24.

The government scrambled to respond to the crisis, with countries around the world offering aid.

“There are some epidemiological estimates that say we are closing in on a peak, but these are all projections,” said Chandrika Bahadur, chair of the Lancet Covid-19 Commission India Task Force, on May 3. “So it’s hard to tell whether the peak will come in the middle of May … or whether it will take a little bit longer.”

But even if the wave peaks and daily case figures decline, scientists warn that the country will continue to see high mortality throughout the month, since deaths lag behind the rise in infections.

Here’s what you need to know about the crisis in India.

How did it get so bad?

Infections began creeping upward in early March, but accelerated rapidly – the number of daily cases by the end of the month had jumped six times higher than at the start of the month. That exponential rise has continued into May.

The second wave hit so much harder because people were unprepared, experts say. The first wave peaked in September, and daily cases declined steadily in the following months; the apparent recovery seemed so successful that the country’s health minister declared in early March they were “in the endgame” of the pandemic.

And the country’s vaccination drive, among the world’s largest and most ambitious, got underway in January.

Residents relaxed Covid-safe practices like social distancing, and authorities were looser in their enforcement. Although some states stayed cautious and made preparations for a second wave, none of it was enough – and nobody foresaw the massive coming wave.

“No one saw the extent of the surge,” said K. VijayRaghavan, principal scientific adviser for the Indian government. “As the previous wave came down, there was in all of us a feeling that this was something which had been dealt with substantially. We saw signs of a next surge, but the scale and the intensity of it was not clear.”

The crisis was made worse by a slow response from the central government. Though some state ministers and local authorities began taking action since February, there appears to have been a vacuum of leadership within the central government, with Prime Minister Narendra Modi staying largely silent on the situation until recent weeks.

Modi finally broke his silence on April 20, acknowledging the urgency of the situation in an address to the nation, and launched a number of emergency measures to relieve the burden on states and hospitals. But by then, some critics say, the damage was done.

And the real impact could be much worse than official figures suggest, experts say, citing a serious underreporting issue.

Only about 34% of deaths are happening in hospitals and facilities, said Dr. Hemant D. Shewade, a doctor specializing in community medicine – meaning many fatalities that occur at home or elsewhere may be missed in the official count.

“Our case detection rate is around 3.6%,” he added. “I can safely say that our estimated Covid deaths are five times (the reported figure).”

Where is it happening?

New Delhi, the national capital, was badly hit by the second wave. The union territory of Delhi, where New Delhi is located, was placed under lockdown on April 19, a move which has since been extended several times.

Hospitals across Delhi are reporting fatal oxygen shortages. Eight people, including a doctor, died at a New Delhi hospital after the facility ran out of oxygen on May 1. The same problem saw 20 critically ill patients die at another hospital on April 23.

The western state of Maharashtra has been worst affected, with a number of restrictions in place including weekend lockdowns. Public gatherings have been capped at four people, while public transit across districts and within cities has been limited to essential services and “unavoidable events” like funerals. The restrictions have been extended several times, and are in place until May 15.

As of May 11, at least 24 of India’s 36 states and union territories are under some form of Covid restrictions, according to CNN data compiled from state governments. Apart from Delhi, a number of states and territories have imposed local lockdowns, including Haryana, Uttar Pradesh, Bihar, Gujarat, and Kerala.

Who’s being affected?

Current Covid patients span nearly every age group, including young people, experts say.

“The virus and its second wave is hitting the younger people, and even children, in a way it had not in its first wave,” said Barkha Dutt, an author and journalist based in New Delhi. “We’ve met 18-day-old babies that are fighting for their lives inside ICUs.”

However, government statistics show that proportionally, young people are not being affected more during the second wave than the first wave. In both waves, young people make up a similar percentage of all patients – the apparent rise in young patients could be because the overall case figures are so much higher this time around.

Part of it could also have to do with India being a young country, said Dr. Lancelot Pinto, a consultant pulmonologist at P.D. Hinduja Hospital in Mumbai. The median age of the population is 27, which means that when there’s a virus affecting the whole country at such a high speed, “there are bound to be a lot of young people coming to the hospital.”

The highest mortality, however, is still seen among patients age 70 and above, said Babu of the Public Health Foundation of India – “which means that we need to be protecting the elderly by providing critical care.”

What about the variants?

Scientists are still studying a coronavirus variant first identified in India called B.1.617, to gauge what effect, if any, the mutation has.

The World Health Organization has classified it as a variant of concern, saying on May 10 that it shows a possibility of increased transmissibility.

India’s National Center for Disease Control (NCDC), as well as top epidemiological experts in the country, have previously said that the surge in cases in some states showed a correlation with the rise in the variant.

Some of the country’s top epidemiological experts have also suggested there may be a correlation.

“In Maharashtra we saw (the Indian variant) go up, we saw an outbreak. We are seeing it go up in Delhi, we are seeing an outbreak,” said Anurag Agrawal, director of the Institute of Genomics and Integrative Biology, at a webinar in April.

Crowded areas in hard-hit cities that saw nearly 50% antibody levels during the first wave were still reporting positivity rates of more than 25%, Babu said in April. “Clearly, it means that any protection against the earlier variant is not really useful because of the newer variant spreading faster.”