States say they don’t have enough doses for people aged 18-45, as new coronavirus cases pass 400,000.
India has become the first country to report more than 400,000 new coronavirus cases in a single day, as its nationwide vaccine drive launches amid a supply crisis.
Some 3,523 deaths were officially recorded in the past 24 hours – but the real figure is thought to be far higher as many fatalities go unreported.
As of today, all adults in India are eligible to be vaccinated.
But several states say they do not have the doses to carry out the exercise.
India had previously focused on vaccinating frontline workers and the over-45s. The country is facing acute shortages of medical oxygen and hospital beds, as a devastating second wave of coronavirus batters its health system.
About 150 million shots have been given, equivalent to 11.5% of India’s 1.3 billion people.
Despite being the world’s biggest producer of vaccines, the country is suffering an internal shortage and has placed a temporary hold on all exports of AstraZeneca to meet domestic demand.
More than 13 million people aged 18-45 have registered for the jab, but states including central Madhya Pradesh and hard-hit Maharashtra have said they will not start vaccinating this age group on 1 May as planned due to supply problems.
Delhi Chief Minister Arvind Kejriwal asked people not to queue up for injections as the Indian capital had not yet received doses.
“As soon as vaccines arrive we will let you know, then you can come for shots. We appeal to you not to crowd vaccine centres in the next few days,” Mr Kejriwal said.
“Many across the country have registered for vaccines but we have not received stocks. We are in regular touch with companies and we hope to get the vaccines in a day or two.”
Experts believe India should ramp up vaccination in areas of high transmission and in five states where elections are being held.
Bhramar Mukherjee, a biostatistician at the University of Michigan, told the BBC the country needed to administer 10 million shots daily “instead of being complacent with three million” doses a day.
“I do feel frustrated that India did not roll out the vaccination drive more aggressively while the curve was in its valley,” Dr Mukherjee said.
Since the pandemic began, India has confirmed more than 19 million cases – second only to the US. It has also reported more than 200,000 deaths.
The US has said it will restrict travel from India, beginning on Tuesday, to try to stop the spread of Covid-19. Australia has gone a step further, making it temporarily illegal for its citizens to return home from India.
Hospitals in the country have been suffering from shortages of oxygen and beds.
At one hospital in Delhi, several people died on Saturday when critically ill patients were left without oxygen for about 80 minutes before re-supply tankers arrived, according local media reports.
Vijay Gupta, 62, was gasping for air outside a hospital in the south-east of India’s capital because all of its beds were full.
“We have been roaming around since 6am looking for a bed,” a friend told Reuters. “Where shall we go?”
Also on Saturday, a fire at a hospital in the western city of Bharuch killed 12 people – the latest in a number of deadly hospital fires across the country this week.
Crematoria have been struggling to cope with the masses of Covid deaths, and some have been forced to build makeshift funeral pyres.
“Come back to us. How will we live without you?” one woman wept on Friday as she waited with the body of her husband at a crematorium in the capital.
India has been using two vaccines – the Oxford-AstraZeneca jab (known locally as Covishield) and another made by Indian firm Bharat Biotech (Covaxin).
The Russian-made Sputnik V vaccine has also been approved for use, and the first doses are expected to arrive on Saturday. It’s not yet clear how large the shipment will be.
Earlier this week, Brazil’s health regulator refused permission for Sputnik V to be imported there, citing concerns about its development and safety. The vaccine’s developer called the move political and said it would sue the regulator.
Vaccination is voluntary. State-run clinics and hospitals are offering free jabs, but people can also pay 250 rupees ($3.4; £2.4) a dose at private facilities.
The government is spending around $5bn to provide free doses at state-run clinics, public health centres and hospitals.
People can experience side effects from vaccines.
India has a 34-year-old surveillance programme for monitoring “adverse events” following immunisation. Experts say a failure to transparently report such incidents could lead to fear-mongering around vaccines.
India has so far reported 18,904, “adverse events” after vaccination. Most of these events were “minor” – anxiety, vertigo, giddiness, dizziness, fever, and pain – and all patients had recovered, the government said.
It found the “deaths happened in cases where the person had underlying conditions, including heart problems, high blood pressure and diabetes”.