Covid live news: China shuts another city to contain surge; chaos as 3,500 more flights cancelled | World news

Hundreds of thousands more people were ordered to stay at home in northern China on Tuesday, joining millions under strict lockdown in Xi’an as the government tries to contain a worsening outbreak of Covid-19.

Yan’an, which is about 300km (186 miles) from Xi’an, ordered the closure of businesses on Tuesday and told hundreds of thousands of people in one district to stay indoors.

China has followed a “zero-Covid” strategy as Beijing prepares to welcome thousands of overseas visitors to February’s Winter Olympics.

But authorities have faced a resurgent virus in recent weeks, reporting 209 infections on Tuesday – the highest single-day tally since March last year, when the virus was only beginning to spread around the world from the city of Wuhan.