Good morning, I’m Tim Walker with today’s essential stories.

World nearing ‘tipping point’ as coronavirus crisis hits Iran

Experts have warned the world is approaching a “tipping point”, at which the global spread of the Covid-19 coronavirus will be impossible to halt. Turkey and Pakistan have closed their borders with Iran, following the reported deaths of at least 50 people from the virus in the Iranian city of Qom. Italy has imposed draconian measures to try to contain an outbreak in the north of the country, while the South Korean city of Daegu is on lockdown after the country’s infections tripled to 602 over the weekend.

Wuhan restrictions. China has reversed its announcement that certain travel restrictions would be lifted on the city of Wuhan, where the outbreak originated, and delayed its annual parliamentary meeting.

Stock market. European markets fell heavily on Monday morning as the economic impact of the coronavirus crisis continued to deepen.

Runaway Sanders sets his sights on Super Tuesday

Facebook Twitter Pinterest Sanders greets supporters at a campaign rally in California. Photograph: Barcroft Media/Barcroft Media via Getty Images

After his crushing caucus victory in Nevada – bolstered by the support of Latino voters – Bernie Sanders has set his sights on the Super Tuesday states, including Texas and California, as a single centrist challenger to his candidacy fails to emerge from the crowded Democratic field. It’s time for the party to unite behind the progressive senator from Vermont, says Nathan Robinson. Joe Biden’s best remaining hope is to do well next weekend in South Carolina, where the billionaire Tom Steyer has qualified for Tuesday’s TV debate.

Billionaire candidate. In the second part of a Guardian investigation of Mike Bloomberg’s campaign, Amanda Holpuch asks how the billionaire is spending his campaign dollars, and whether the spree could really secure him a win.

Trump approval up as aide ‘politicises intel’ against Sanders

Facebook Twitter Pinterest Trump and the Indian prime minister, Narendra Modi, wave to the crowd at a ‘Namaste Trump’ rally in Ahmedabad on Monday. Photograph: Aijaz Rahi/AP

A new Gallup poll has given Donald Trump the first net positive approval rating of his presidency, an indicator of the danger he poses to Democrats at November’s election. His national security adviser, Robert O’Brien, has been criticised by Democrats for “politicizing intelligence” for saying he has not “seen any intelligence that Russia is doing anything” to help re-elect Trump, while apparently crediting reports that Moscow is backing Sanders in the Democratic primary.

Namaste Trump. After Trump hosted the populist Indian prime minister, Narendra Modi, at a rally in Houston in September, Modi on Monday returned the favour, feting the US president at a vast “Namaste Trump” rally in Ahmedabad, India. Live coverage here.

Assange extradition hearing begins in London

Facebook Twitter Pinterest An Assange supporter outside Woolwich Crown Court in London. Photograph: Hannah McKay/Reuters

The legal fight over the future of the WikiLeaks founder, Julian Assange, will heat up again on Monday, as lawyers representing the US government lay out their arguments for his extradition at a hearing in London. The US wishes to put Assange on trial on espionage charges over WikiLeaks’ publication of diplomatic cables in 2010 – charges that carry a maximum sentence of 175 years in prison.

Lengthy process. The judge is unlikely to rule on Assange’s extradition until later this year. The losing side will probably appeal. And even then the UK government retains the final say over Assange’s fate.

Cheat sheet

The 94-year-old prime minister of Malaysia , Mahathir Mohamad, has resigned from office after being accused of backtracking over a deal to hand power to his coalition partner.

Two Islamic Jihad fighters have been killed by Israeli airstrikes amid a fresh burst of violence in the Gaza Strip.

Philip Morris, one of the world’s biggest tobacco companies , made plans for a $1.27bn tobacco transition fund to be spent by public bodies in the UK, to persuade British smokers to give up cigarettes in favour of the company’s own alternative products.

Barbara B Smith, the model, restaurateur and lifestyle guru often described as “the black Martha Stewart”, has died aged 70 after suffering from early onset Alzheimer’s disease.

Must-reads

Facebook Twitter Pinterest More than half the babies born in wealthier countries since 2000 may reach their 100th birthdays. Photograph: GETTY IMAGES

How to stay healthy as 100-year-lifespans become routine

A 60-year-old in the west today has an even chance of living to 90, a 40-year-old can expect to live to 95, and newborn in the UK today has a 50% chance of living to 105. Amelia Hill asks how we can stay healthy throughout an increasingly lengthy old age.

Behind the long fight to diversify space

Film-maker Laurens Grant’s new documentary, Black in Space, concerns “the forgotten chapter of the space race”, she tells Adrian Horton: the efforts by both the US and the Soviet Union to put a person of colour in space.

The 10 biggest myths in fitness

Despite the never-ending churn of new fitness fads and exercise regimes, the fundamentals remain the same. Is running really bad for your knees? Is soreness a sign of a good workout? Joel Snape explodes the 10 biggest myths of fitness.

How gas wells could block a 6,000-year-old migration route

The Trump administration’s harsh treatment of migrants even extends to the animal kingdom, reports Cassidy Randall: a plan to create 3,500 new gas wells in Wyoming would block a route used annually by the pronghorn for some 6,000 years.

Opinion

This year, the global community is to rededicate itself to halting biodiversity loss. Basile van Havre and Francis Ogwal, the co-chairs of a UN biodiversity working group, say that is possible only with the engagement not just of governments, but of their citizens, too.

Governments and societies need to determine priorities and allocate financial and other resources, internalise the value of nature, and recognise the cost of inaction. Only then can we achieve the shared vision of ‘living in harmony with nature by 2050’, agreed by world governments 10 years ago.

Sport

After knocking out Deontay Wilder in the seventh round on Saturday, Tyson Fury says he expects to face the American for a third time, rather than a unification fight with fellow Brit Anthony Joshua. Kevin Mitchell says Fury has earned the right to be regarded as the best heavyweight in the world, while Sean Ingle traces the Gypsy King’s path from addiction to redemption.

Since Daryl Morey tweeted his support for anti-government protests in Hong Kong in October, NBA games have been blacked out on Chinese state TV. Following a months-long standoff, the league is reportedly close to repairing its relationship with China, but the damage has been “substantial”, as Tom Kludt reports.

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