India's Taj Mahal to reopen in September with social distancing and face masks mandatory

India's top tourist attraction, the Taj Mahal, is set to reopen more than six months after it was shut, even as the vast nation battles soaring coronavirus infections.

India, home to more than 1.3 billion people, on Monday, overtook Brazil to become the world's second most-infected nation with more than 4.2 million cases, behind only the US.

"The Taj Mahal will reopen on Monday, September 21. All Covid-19 protocols, such as physical distancing [and] masks, will be followed," Amit Srivastava, northern Uttar Pradesh state's Tourism Department deputy director, said on Tuesday.

Visitors will be limited to 5,000 a day, down from the usual daily average of 20,000, he said.

One of the New Seven Wonders of the World, the shining marble mausoleum south of the capital, New Delhi, has been closed since mid-March as part of India's strict virus lockdown.

Uttar Pradesh, home to the city of Agra where the Taj Mahal is located, is one of the worst-hit states in India, with more than 270,000 virus cases recorded so far.

India has pushed ahead with reopening to boost its virus-battered economy even as infections have steadily increased.

Since August, the country has been reporting the highest single-day rises in the world.

On Monday, the metro, which serves India's sprawling capital New Delhi and adjoining areas, also resumed operations after five months.

Safety precautions are in place to minimise the risk of transmission on the usually crowded service. Only asymptomatic people were allowed to board the trains, with masks, social distancing and temperature checks mandatory.