The message started with an outlandish claim: The coronavirus was retreating in India because of "cosmic-level sound waves" created by a collective cheer citizens had been asked to join.

Messages were pinging from phone to phone across this country of 1.3 billion saying the applause Prime Minister Narendra Modi had organized for health workers had been detected by a "bio-satellite" that confirmed the weakening of the virus.

Soon, Siddhart Sehgal's family group chat on WhatsApp was buzzing with messages hailing Modi as India's savior.

It of course wasn't true.

As India and other South Asian nations work to stop the spread of the virus, they face another battle: reams of misinformation.

With the pandemic starting to gain a foothold in the region, social media sites are rife with bogus remedies, tales of magic cures and potentially hazardous medical advice. Experts are urging caution and warning that the "coronavirus infodemic" could have disastrous consequences.

Its a trend also seen elsewhere and governments around the world have been urging citizens not to listen to or spread rumors about the pandemic.

So far it hasn't worked in South Asia, a region where online misinformation has in the past had deadly consequences such as lynchings, arson and communal riots where neighbors turn on one another.

On Tuesday, Indians were ordered to stay indoors for three weeks in the world's biggest coronavirus lockdown. In announcing the move, Modi reiterated the danger of misinformation.

"I appeal to you to beware of any kind of rumors or superstitions," the prime minister said.

Earlier appeals against virus rumors have yet to prove effective.

Poultry sales in India plunged following false claims that chickens were linked to the pandemic. Racial attacks against people from the country's northeastern states increased after rumors spread that they carried the virus.

On Sunday, people in a remote village in Manipur state locked themselves inside their homes because of rumors that fumigants were being sprayed from the sky to kill the virus.

The government has asked social media companies to launch awareness campaigns about virus misinformation. It also set up a government WhastApp channel where people can ask questions about the virus and vet claims they hear.

Still the falsehoods spread.

On Monday, Amitabh Bachchan, a top Bollywood star who has more than 40 million Twitter followers, said clapping and blowing conch shells would "destroy virus potency." He later deleted the tweet after facing criticism.

Elected representatives from Modi's Bharatiya Janata Party have also offered bizarre claims of cures for the virus, ranging from cow urine and cow dung to cloves "energized by mantras."

Rumors have spawned concerns elsewhere in the region as well.

In Bangladesh, some clerics claimed Muslims would not be affected by the virus and exhorted tens of thousands of people to gather for a mass prayer last week despite concerns about the health risk.

One preacher claimed to have interviewed — in his dream — a man in Italy to obtain a cure for the virus.

When a journalist at a leading private television station reported about the misinformation, he received death threats.

"We are monitoring and doing our part, but it (misinformation) comes from various sources, one after another," said Zakir Hossain, a spokesman for the Bangladesh Telecommunication Regulatory Commission. "This is a huge task."

Pakistan too has had to fight against religious leaders urging the devout to attend prayers and promising their faith will protect them. A cleric in Lahore made a video saying it was impossible to catch the virus while praying and said he should be hanged if he were wrong. Police arrested him instead and he made another video urging people to take the pandemic seriously and wash their hands.

On the outskirts of Islamabad the army was called in to shut down a mosque after its prayer leader despite exhibiting symptoms kept his mosque open.

In Sri Lanka, authorities warned that legal action will be taken against people who spread false information over social media. Several people have been arrested.

Pakistan has been the worst hit South Asian nation with some 1,200 virus cases reported. India has reported more than 725.

For most people, the virus causes mild or moderate symptoms, such as fever and cough that clear up in a few weeks. But for some it can cause more severe illness, including pneumonia and death.

There are concerns that if cases were to surge in South Asia, it would overwhelm already strained health systems.

Sumaiya Shaikh, an editor for fact-checking website ALT News, has been tracking misinformation on messaging apps in India since before the pandemic.

In January, when the virus was still largely limited to China, Shaikh said India experienced a deluge of false WhatsApp messages claiming that Chinese police were shooting people suspected of having the disease.

When India started having cases, rumors about cures began, Shaikh said.

"This misinformation has reached a critical mass and is jeopardizing public health," she said.

The search for accurate virus information in India is complicated by advice issued by a parallel health ministry, the Ministry of AYUSH, created in 2014 by Modi to promote alternative therapies such as yoga and traditional Ayurveda medicine.

The ministry has recommended herbs and homeopathy as cures for the virus, along with frequent sipping of water boiled with basil leaves, crushed ginger and turmeric.

P.C. Joshi, a medical anthropologist at the University of Delhi, said that advice "falls into the category of misinformation which can be hazardous for public health."

The ministry did not respond to requests for comment.

The messages spreading online, often shared among friends and relatives, have unnerved many Indians who don't know whether to take them seriously.

When the messages claiming that the virus was retreating in India spread on WhatsApp, members of the Sehgal family wanted to leave their home and join others outside celebrating. But Siddhart stopped them.

"My family usually believes whatever they get on WhatsApp regarding the virus," he said. "It's hard to explain to them that most of it is fake."

Japan's cherry blossoms are in full bloom, but flower viewing has come to an abrupt halt in Tokyo because of the coronavirus.

Tokyo Gov. Yuriko Koike has repeatedly asked the city's 13 million residents to stay home this weekend, saying the capital is on the brink of an explosion in virus infections. She warned of a possible hard shutdown of the city if the spread of the virus doesn't slow.

On Friday evening, access was blocked to Ueno Park, a favorite spot for "hanami," or cherry blossom viewing. Signs said "No parties" and "Danger no entry."

The empty park was a sharp change from last weekend, when people came in droves after the central government announced an end to national school closures, leading many to think that the outbreak was under control, when it was actually worsening in the capital.

Koike repeated her stay-at-home request Friday, asking Tokyoites to postpone their flower viewing until next year. "The cherry blossoms will surely bloom next year. Our priority right now is to overcome this difficult time," she said.

Amusement parks, zoos and aquariums, as well as some coffee shops and department stores, will be closed for the weekend. Officials are particularly concerned about asymptomatic young people spreading the virus.

Daichi Harada was with his dog getting some fresh air in the park after being at home for an extended period.

"Tokyo ordered us to stop cherry blossom viewing," he said as left. "It's our duty to stay home."

From the sun-soaked beaches of Thailand to the foothills of Mount Everest in Nepal, tourists across Asia are finding their dream vacations have turned into travel nightmares as airlines cancel flights and countries close their borders in the fight against the coronavirus pandemic.

Hundreds of tourists escaping cold weather in Europe were scrambling this week to find alternative ways to return home from the Thai island of Phuket in the Adaman Sea.

Ksenia Vostriakova and her friends were scheduled to fly back to Moscow on an April 3 Singapore Airlines flight, but it was among those canceled when the airline slashed its operations. They have booked a flight on Qatar Airways for April 6 and are hoping nothing else changes.

"Now we're really worried that this flight also might be canceled," Vostriakova said, adding that their Thai visas run out in mid-April. "We might still stay here because everything changes."

Thailand went under a state of emergency this week as the government gives itself new powers to deal with the virus crisis. The country, which last year welcomed 39 million tourists, announced it was closing its borders to nearly all foreigners. It's national airline Thai Airways said it was suspending almost all of its flights.

It's a trend seen around the region and the world. The Airports Council International Asia-Pacific said Friday that 12 major hubs in Asia-Pacific had seen an average decrease in air traffic of more than 80% in the second week of March versus the same period last year.

Up to 10,000 tourists are believed to be stranded in Nepal after the government ordered a complete lockdown that halted all flights and road travel to prevent the spread of the virus, the country's tourism board said. Most businesses and government offices were also shut.

Spring is the tourist season for Nepal when thousands of visitors come to hike the mountain trails.

At the Lukla Airport, the only gateway to the Mount Everest region, there were more than 200 trekkers stranded, according to Dhurba Shrestha, an airport official. Even if the highways were open, the closest road is three days trek downhill.

Officials were working on arrangements of special flights to at least get tourists back to the capital, Kathmandu.

The German government on Friday arranged a rescue flight — a Qatar Airways charter — that left the capital with 305 people on board, mostly German nationals.

In Kathmandu's tourist enclave, visitors could still be found wandering around empty streets. A handful of restaurants and hotels were still open, but most shops were shuttered. Police were blocking locals from moving around but not tourists.

"We were supposed to leave on March 21 but we are still in Nepal and waiting for our embassy to help us arrange a flight," said New Lee Kuan, from Malaysia.

The Indian Ocean island nation of Sri Lanka said that it was ready to help an estimated 18,000 tourists return home either via scheduled flights that are still operating or special charters if required. The country is under a nationwide curfew until at least next week.

In Indonesia, more than 2,500 foreign tourists were stranded in Bali, the most famous of the country's more than 17,000 islands. The government has granted all tourists automatic visa extensions, a move made after long lines formed at immigration offices.

"This is good news that helped us a lot," said Ruben Evert Ernst, a German on vacation with his partner whose visa had been set to expire in a few days.

Visitors to Thailand haven't been so lucky. Hundreds of tourists seeking visa extensions were crowded Friday under a row of awnings next to a makeshift immigration office that's been set up on the outskirts of Bangkok after throngs formed at the main building. There wasn't enough room for the tourists to keep their distance and stay in the shade so most were pressed up almost against one another.

"I woke up today at 5:30 to get here on time so it's very stressful," said Murdoch Baghaie, from Sacramento, California. "I'm supposed to be a tourist enjoying the scenery. Nothing like enjoying Thailand anymore."

Shopping malls, bars, sit-down restaurants, public swimming pools and many other places have all been ordered closed in Thailand.

At least for now, Phuket's beaches remain open. That's good news for Russian tourist Vitaliy Kurikov, who has been spending his days playing with his son on the white sands of Bagntao beach.

"If they close the beaches, I really don't know what to do," he said.

No new confirmed cases of the novel coronavirus disease (COVID-19) were reported Tuesday in Wuhan, the former hardest-hit city in central China's Hubei Province.

The health commission of Hubei, of which Wuhan is the capital, said Wednesday the total confirmed cases of COVID-19 in Wuhan and Hubei remained at 50,006 and 67,801 by Tuesday.

Hubei saw three deaths, two of which were in Wuhan.

The central Chinese province also registered zero increase in new confirmed cases on Tuesday. No new suspected cases were reported on Tuesday, as well.

The province saw 487 patients discharged from hospital after recovery on Tuesday. Among the 3,772 patients being treated in hospital, 1,050 were still in severe condition and another 318 in critical condition, according to the commission.

India will begin the world's largest lockdown on Wednesday, Prime Minister Narendra Modi announced in a TV address, warning citizens to stay inside or risk inviting the pandemic into their homes, and pledging $2 billion to bolster the country's beleaguered health care system.

"To save India and every Indian, there will be a total ban on venturing out," Modi said Tuesday night, acknowledging that the 21-day lockdown would be a major blow to the economy, but that the alternative could set the country back 21 years.

The move puts nearly one-fifth of the world's population under lockdown.

Indian health officials have reported 469 active cases of COVID-19, the disease caused by the virus, and 10 deaths. Officials have repeatedly insisted there is no evidence yet of communal spread but have conducted relatively scant testing for the disease. In a country where tens of millions live in dense urban areas with irregular access to clean water, experts have said communal spread is inevitable.

For weeks, while the coronavirus wracked neighboring China and other parts of Asia, India's infection toll stood at just three, all students in the Chinese epicenter, Wuhan, who were treated in their home state of Kerala and recovered from the disease.

But since the World Health Organization declared the coronavirus a global pandemic, triggering India's government to invoke a British Raj-era epidemic act giving it sweeping powers to contain the disease, the cases have been growing rapidly and, according to Modi, have the potential to "spread like wildfire."

In recent days, India has been gradually expanding stay-at-home orders and has banned international and domestic flights and suspended passenger service on its extensive rail system.

Essential service providers, including hospitals, police and media had been exempted from the stay-in-place orders, and many grocery stores and pharmacies remained open.

Modi called Tuesday's order a "total lockdown" and did not address whether any service providers would be exempt, but said that "all steps have been taken by central and state government to ensure supply of essential items."

It was not clear what this would mean for about 300 million Indians who according to official data live below the poverty line.

Indian finance minister Nirmala Sitharaman said Tuesday that a comprehensive relief package would be announced soon.

The lockdown "has essentially drawn a laxman rekha on our doors," Modi said, referring to a line drawn by the hero of the Hindu epic "Ramayana" to protect his wife's dwelling-place. "You must remember that you will invite a grave pandemic like coronavirus to your homes if you step out."

Indian virologist Dr. T. Jacob John said before the wholesale lockdown was announced on Tuesday that India was being forced to take extreme containment measures after failing to mitigate the problem earlier on, when the caseload was light.

"There would have been time because the wolf was not yet at the door. Now today the wolf's inside the door and India's supposed to calmly respond with a wolf in the corner," he said.