Good morning.

       We’re covering Kim Jong-un’s health, Hong Kong’s protest movement and Earth Day’s very special birthday (hint: it’s the big 5-0).

       A Korean mystery: Where’s the North’s leader? South Korean officials are questioning the accuracy of a report by Daily NK, a website based in Seoul that relies on sources in North Korea, that Kim Jong-un, 36, is recovering from heart surgery performed on April 12.

       Mr. Kim last appeared in public on April 11, when he presided over a meeting of the Politburo of the ruling Workers’ Party. It is not unusual for senior North Korean leaders to stay out of view for weeks at a time, but when Mr. Kim didn’t appear on April 15 to commemorate the birthday of his grandfather, Kim Il-sung, the founder of the regime, it triggered speculation about his health and whereabouts.

       Context: The inner workings of the top leadership in Pyongyang have been cloaked in such secrecy that disappearances like these always catch the attention of analysts. When Mr. Kim’s father, Kim Jong-il, died in 2011, foreign intelligence officials didn’t know until the news was announced two days later on North Korean television.

       Trump says he’ll halt immigration President Trump plans to shut down immigration to the U.S. in an attempt to protect American workers once the nation’s economy begins to recover from the coronavirus shutdown.

       In a few hours, the president is expected to announce a temporary pause in the issuance of most green cards, a move that will close the U.S. off to tens of thousands of people, a person familiar with the president’s plans said. It was not immediately clear what legal basis the president would claim to justify the move.

       Several people familiar with the plan said the administration was also weighing a large expansion of travel restrictions that had already reduced the number of travelers from Europe and China.

       Context: Mr. Trump’s denigration of immigrants was the centerpiece of his 2016 presidential campaign. As he seeks re-election to a second term, the president has made clear that he intends to energize his supporters by continuing to stoke anti-immigrant sentiment.

       Here are the latest updates about the pandemic as well as maps of the outbreak.

       At least 28,000 more people have died over the past month than have been officially reported, a review of mortality data in 11 countries shows. The totals include deaths directly caused by Covid-19 as well as those stemming from other illnesses that couldn’t be treated by overwhelmed health care systems.

       The coronavirus pandemic is likely to double the number of people facing acute hunger this year, according to a new report from the World Food Program.

       Ramadan begins this week. Our Cairo bureau chief reports on how the outbreak has cast a shadow over the holy month of fasting for the world’s 1.8 billion Muslims.

       The Times is providing free access to much of our coronavirus coverage, and our Coronavirus Briefing newsletter — like all of our newsletters — is free. Please consider supporting our journalism with a subscription.

       How a crackdown in Hong Kong could backfire The coronavirus epidemic has helped mute antigovernment demonstrations in the Chinese territory — for now.

       But a government roundup of prominent pro-democracy figures over the weekend, in tandem with increasing rhetoric from Beijing, could energize protesters when social distancing rules are eased.

       Here’s a look at the standoff and what recent moves by both sides could mean in the coming months.

       If you have 7 minutes, this is worth it

       Lessons from Australia’s wildfires With a long and devastating fire season finally over in Australia, scientists and disaster officials are working on new fire-prediction technology to help firefighters work faster and more safely when the blazes return in just a few months.

       Here’s the catch: Advancements in technology are important, but what is really needed is tackling climate change, says Greg Mullins, a former commissioner of Fire and Rescue New South Wales. “It’s a bit like going to a gas fire and putting out all the houses and burning cars around it but not turning off the gas.”

       Here’s what else is happening South China Sea tensions: Two U.S. warships have sailed into disputed waters in the South China Sea, sharpening the rivalry between the U.S. and China while much of the world is under lockdown during the coronavirus pandemic. Chinese and Australian warships have also powered into nearby waters.

       Oil prices plunge: The record-setting collapse of the U.S. oil benchmark spread to other parts of the oil market as traders concluded that output remains far too high and storage is running out. The price slides underscore the industry’s disarray as the coronavirus pandemic decimates the global economy.

       U.S. presidential campaign: New fund-raising figures show Joe Biden, the presumptive Democratic presidential nominee, is $187 million behind the Republicans and President Trump, who spent the last three years amassing campaign contributions.

       Snapshot: Above, the golden lion tamarin, which lives only in Brazil. Conservationists managed to get a construction company to agree to build a forested overpass for animals, the first in Brazil, to allow the endangered tamarins to expand their habitat.

       Wanderlust: We asked four Travel contributors to share their memories of trips that still impart a sense of wonder and hope, including a bittersweet return to Hyderabad, India, and a college student’s self-discovery in Australia.

       What we’re reading: This remembrance in Rolling Stone. Kevin McKenna, a deputy editor on the Business desk, suggests this “wonderful account of the avid concert-going life of my friend Ron Louie,” a music superfan and designer who helped The Times launch its first website in the 1990s. He died of complications from the coronavirus in March.

       Now, a break from the news

       Cook: Mastering the technique of cooking pasta and sauce together in a single pot will save you time at the stove — and the sink. The ratio of pasta to water is crucial to the dish’s success.

       Watch: This is exactly the right time to stream documentaries about very strange things (competitive endurance tickling, for instance). And the designer Mary Ping made a bag out of newspaper for T, The Times’s style magazine.

       Cope: Here’s how to set up your home work space so you can put away your “office” at the end of each day. And if you’re feeling lonely, we have some ideas to help.

       Read: In “Sigh, Gone,” the immigrant experience haunts a Vietnamese-American long after he and his family assimilate in Carlisle, Pa.

       We have more ideas about what to read, cook, watch and do while staying safe at home.

       And now for the Back Story on … Earth Day turns 50 Today is Earth Day, the annual event established as a way to raise awareness about the state of our planet. John Schwartz, one of our reporters covering climate change, spoke about what Earth Day means five decades later.

       In broad terms, what has changed since 1970?

       The air over the U.S. is much cleaner, and so is the water we drink in most parts of the country. We don’t use DDT or asbestos. But other threats have arisen. The biggest of those — the issue that wasn’t really on the radar for most people in 1970 — is climate change. Scientific evidence has grown and scientific consensus has gelled, and so now we recognize that there are threats that are more fundamental, and ultimately more harmful, than we ever knew 50 years ago.

       With the coronavirus crisis dominating our lives, is Earth Day relegated to a second-tier event this year?

       It’s anything but second-tier, but it’s virtual. You won’t have millions marching in the streets, but there are activities all around the world. Young climate strikers are speaking out. The modern-day equivalents of the 1970 “teach-ins” are happening online.

       How can people celebrate Earth Day from home?

       We’ve put together a great package of stories that provide a crash course on climate change, help readers pick out books about climate change, introduce them to the original organizer of Earth Day and more. And there’s so much going on at earthday.org and on the websites of other climate- and environment-oriented groups that there’s something for everyone.

       That’s it for this briefing. See you next time.

       — Carole

       Thank you

       To Ali Slagle for the recipe, and to Theodore Kim and Jahaan Singh for the rest of the break from the news. You can reach the team at briefing@nytimes.com.

       P.S.

       ？ We’re listening to “The Daily.” Our latest episode is about coming rulings from the U.S. Supreme Court.

       ？ Here’s our Mini Crossword, and a clue: Currency of Poland (five letters). You can find all our puzzles here.

       ？ Wirecutter, a Times product review site, has started a three-day email course to help make the transition to working at home a bit easier.