On Sunday, Moscow had the highest daily coronavirus death toll for a Russian city, as countries across the Asia-Pacific region extended or reimposed restrictions to combat new outbreaks of infection.

The pandemic has now killed nearly four million people worldwide, but vaccination campaigns have reduced infection rates in many wealthy countries, though the Delta strain of the virus remains a concern.

According to the World Health Organization, the variant is now present in 85 countries and is the most contagious of any Covid-19 strain identified. Still, in much of Europe and the United States curbs on daily life are easing as vaccination programmes bear fruit, although Russia is grappling with a deadly third wave.

The Russian capital recorded 144 Covid-19 deaths in the last 24 hours on Sunday, a day after Saint Petersburg set the previous high. Saint Petersburg has hosted six Euro 2020 matches and is set to host a quarter-final on Friday, with spectator numbers capped at half but expected to be in the 26,000 range.

Since mid-June, Russia has seen an increase in new infections caused by the Delta variant. The dramatic increase in cases coincides with officials in Moscow urging vaccine-skeptical Russians to get immunized following the lifting of most anti-virus restrictions late last year. “To stop the pandemic, one thing is needed: rapid, large-scale vaccinations. Nobody has invented any other solution,” Moscow mayor Sergei Sobyanin told state-run television on Saturday.

The Delta variant is also fueling new outbreaks in Southeast Asia and Australia, where authorities have reinstated or extended restrictions. More than five million Sydney residents were subjected to the first full day of a two-week lockdown to contain an outbreak of the strain on Sunday.

Restaurants, bars, and cafes were closed, and stay-at-home orders were issued, effectively leaving the city center deserted.

“Given how contagious this strain of the virus is, we anticipate that case numbers will rise even further in the coming days,” New South Wales state Premier Gladys Berejiklian said. More than 110 Covid-19 cases have been reported in Sydney since a driver for an international flight crew tested positive in mid-June for the Delta variant. The flare-up has been a shock for a place that had returned to relative normality after months with few local cases.

Blain Cunneen, a professional musician, said his work — performing gigs, recording studio sessions, and teaching students — had gone “up in smoke” overnight.

“Everything was almost back to normal… and then, all of a sudden, I got a bunch of emails and texts about everything being cancelled.”

Darwin, Australia’s northernmost city, also went into a 48-hour lockdown on Sunday after a handful of cases were linked to a coronavirus outbreak at a remote gold mine.

“The Northern Territory is now facing its most serious threat since the beginning of the Covid crisis,” Northern Territory Chief Minister Michael Gunner said. In Southeast Asia, similar increases in infections have recently been observed.

Thailand will reimpose restrictions on restaurants, construction sites, and public gatherings in Bangkok beginning Monday in an effort to contain a wave of infections. The country’s most recent wave began in April, when a cluster was discovered in upscale Bangkok clubs. Premier Prayut Chan-O-Cha has stated that he intends to reopen the country fully by October, but this would necessitate meeting a target of vaccinating 50 million Thais in four months.

In neighboring Malaysia, the prime minister announced that a nationwide lockdown that has been in effect for about a month will be maintained, with no date set for the restrictions to be lifted. His government had previously stated that the strict restrictions would be eased gradually as long as there was a decrease in infections, intensive care bed use, and an increase in vaccination rates.

Bangladesh also announced a new national lockdown beginning Monday, with offices closing for a week and only medical-related transportation permitted.