Prime Minister Narendra Modi late Tuesday called on Indians to step up their efforts to battle the coronavirus so that fresh lockdowns are not necessary, as the vast nation reels from an explosion of cases and the capital runs dangerously short of oxygen supplies.

In his first address since the start of the record-breaking new wave of infections, Modi acknowledged that the nation of 1.3 billion people was "once again fighting a big fight".

"The situation was under control till a few weeks back, and then this second corona wave came like a storm," the Indian leader told the nation in a televised speech.

Medical oxygen supplies are running dangerously low in parts of India -- here, people fill cylinders for Covid-19 coronavirus patients at a refill station in Allahabad
Medical oxygen supplies are running dangerously low in parts of India -- here, people fill cylinders for Covid-19 coronavirus patients at a refill station in Allahabad AFP / SANJAY KANOJIA

"It is a big challenge but we have to -- together, with our courage and determination -- overcome it... We have to avoid lockdowns and we need to focus on mini containment zones instead."

India has been struggling to rein in its raging outbreak, with hospitals running out of beds and regional governments forced to reimpose economically painful restrictions.

The South Asian nation has recorded more than three million new infections and 18,000 deaths this month, bringing its caseload to the world's second-highest, after the United States.

Lockdowns and nightly curfews have returned to several parts of India amid a surge in coronavirus cases -- here, a woman walks on an otherwise deserted street in Hyderabad
Lockdowns and nightly curfews have returned to several parts of India amid a surge in coronavirus cases -- here, a woman walks on an otherwise deserted street in Hyderabad AFP / NOAH SEELAM

Its capital and worst-hit city New Delhi entered a week-long lockdown on Monday, with parks, cinemas and malls closed.

Maharashtra state, the epicentre of the recent surge and home to financial capital Mumbai, on Tuesday further tightened restrictions on grocery shops and home deliveries.

All non-essential shops and malls in the western state are currently shut until May 1.

Uttar Pradesh, home to some 240 million people, on Tuesday announced a weekend lockdown from Friday evening, whilst Telangana state in the south became the latest to impose a night curfew.

Some experts have pointed to mass vaccinations as the way out of India's surging coronavirus crisis
Some experts have pointed to mass vaccinations as the way out of India's surging coronavirus crisis AFP / Arun SANKAR

Delhi Chief Minister Arvind Kejriwal, who on Tuesday went into self-isolation after his wife tested positive, called on the national government to supply the capital with oxygen amid a severe shortage.

"Some hospitals are left with just a few hours of oxygen," he tweeted late Tuesday.

Delhi's lockdown prompted tens of thousands of migrant workers to flee the mega-city, in scenes reminiscent of the national shutdown a year ago that inflicted economic and human misery.

Oxygen tankers are seen being boarded on a special 'Oxygen Express' train that would bring back needed oxygen supplies to Mumbai
Oxygen tankers are seen being boarded on a special 'Oxygen Express' train that would bring back needed oxygen supplies to Mumbai AFP / -

Modi said states had to assure migrant workers of support and vaccines so that they would not return to their villages.

"I appeal to states to avoid lockdowns and use them as a last resort," he added.

Graveyards and crematoriums across India are struggling to cope with the surging number of deaths as the nation of 1.3 billion people battles a raging coronavirus outbreak
Graveyards and crematoriums across India are struggling to cope with the surging number of deaths as the nation of 1.3 billion people battles a raging coronavirus outbreak AFPTV / Archana THIYAGARAJAN

The huge surge in infections saw the United States update its travel advisory for India, after the State Department announced Monday it would apply "do not travel" guidance to about 80 percent of countries worldwide, citing the unprecedented risk posed by the pandemic.

"Even fully vaccinated travelers... should avoid all travel to India," the US Centers for Disease Control and Prevention said.

Singapore also boosted restrictions on arrivals from India Tuesday, adding a week to the previously required 14-day quarantine period.

These moves follow Britain's decision on Monday to add India to its "red list", and Hong Kong's ban on all flights from the country.

Meanwhile, Rahul Gandhi, a senior leader of the opposition Congress party and scion of the Nehru-Gandhi political dynasty, tweeted Tuesday that he had tested positive but had "mild symptoms", one day after former prime minister Manmohan Singh, 88, was admitted to hospital with the virus.

In a sign of how dangerously overstretched the hospitals are, people are using social media to appeal for medical supplies for their relatives.

On Monday night, a special "Oxygen Express" train left Mumbai to the industrial southern city of Visakhapatnam, carrying seven empty tanker trucks that should return full in four days.

Modi added that "all efforts are being made" to boost oxygen supplies.

Experts have warned that religious festivals and packed state election rallies have become "superspreader" events -- and some have said mass vaccinations are the only long-term solution.

India kicked off its inoculation drive in mid-January and has administered more than 127 million shots so far.

From May, all adults will be able to get vaccinated, the government announced Monday.

Some local authorities have however been running short of supplies, and India has put the brakes on exports of the AstraZeneca shot.

Covaxin is being administered alongside AstraZeneca's shot in India, while approval has also been given for Russia's Sputnik V.