Having told their populations that wearing masks was all but useless against the coronavirus, several Western countries have performed dramatic U-turns in the last few days.

Foreign governments on Friday stepped up operations to evacuate tens of thousands of tourists stranded by the coronavirus pandemic in remote locations across South Asia, from Everest base camp to beach hotels in Sri Lanka.

Tightened lockdowns across the planet saw nearly half of humanity told to stay at home in a bid to stem the spiraling coronavirus pandemic, as Spain recorded its deadliest day Tuesday and the United States braced for the full impact of the disease.

Harsh lockdowns aimed at halting the march of coronavirus around the world widened on Monday to include Moscow's capital as the death toll mounted and fears grew for the fate of the global economy.

They have been hailed as India's coronavirus "heroes", but doctors, nurses, delivery drivers and other frontline workers have been attacked and in some cases evicted from their homes by panicked residents.

The coronavirus death toll shot past 20,000 in Europe on Saturday, with Italy and Spain each reporting more than 800 dead in one day, as US President Donald Trump pulled back on putting the hard-hit New York region under quarantine.

The United States on Thursday took the grim title of the country with the most coronavirus infections and reported a record surge in unemployment as world leaders vowed $5 trillion to stave off global economic collapse.