Hundreds of millions of people in India, including in its two largest cities, were ordered Wednesday to wear face masks or coverings amid a nationwide lockdown to combat the spread of the coronavirus pandemic.

Residents in the capital New Delhi and financial hub Mumbai, which have a combined population of almost 40 million, as well as in the most-populous state Uttar Pradash where 200 million live, will have to cover their faces in public spaces.

"Wearing of facial masks can reduce the spread of coronavirus substantially," Delhi Chief Minister Arvind Kejriwal said late Wednesday.

"Therefore, it has been decided that facial masks will be compulsory for anyone stepping out of their house."

With masks running short around the world, however, one official told AFP that "face cover will be a more appropriate word".

"Gamcha (a type of cotton cloth) or any cotton cloth which can cover your mouth can also be used," the official, Mrityunjay Kumar, media adviser with UP Chief Minister Yogi Adityanath, said.

The health ministry on the weekend advised all residents in the nation of 1.3 billion people to cover their noses and mouths with homemade reusable face covers.

It also released instructions online on how people could make their own masks.

A rickshaw puller wearing a face mask watches people standing in a queue in New Delhi on April 8. Officials have now made wearing a mask in the Indian capital compulsory
A rickshaw puller wearing a face mask watches people standing in a queue in New Delhi on April 8. Officials have now made wearing a mask in the Indian capital compulsory AFP / Money SHARMA

The new rules came as India's official number of cases rose above 5,200, including 149 deaths.

Experts said authorities need to test more to determine how widely the highly infectious disease has spread in the world's second-most populous country.

The nationwide lockdown was imposed from March 25 for 21 days, with residents permitted to leave their homes only for essential services such as buying groceries and medicine.

But the number of cases has continued to rise, with officials blaming a large religious gathering in March where thousands of people congregated for at least 30 percent of patients.

On Wednesday numerous neighbourhoods and hotspots in Uttar Pradash and Delhi were set to be sealed off, with locals barred from leaving their homes and authorities promising to deliver food and other essential items to their doorsteps.

The drastic move came amid growing debate about whether the lockdown due to be lifted on April 15 should be extended.

Some states and territories, including Maharashtra, where Mumbai is the capital, Tamil Nadu, and Delhi have reported significantly higher numbers of infections compared to others.

The shutdown has badly hit rural migrant workers in the cities, leaving them jobless with hundreds of thousands trying to return to their villages, many on foot.