Indians pose for photos after receiving their inoculations against COVID-19.

After a slow start, India has ramped up its immunisation drive, opening more centres, simplifying the process and turning to social media to spread the word.

More than 3.2 million people got vaccinations on a single day last week, one of the world's highest rates.

Mumbai resident Ramesh Achari hopes to encourage others to get the vaccine:

"I clicked a selfie and I will tell everyone that I came here and got myself vaccinated for coronavirus and will request others also to get vaccinated."

There's a lot at stake and not just for India.

The country - home to nearly 15% of the world's humanity - has confirmed more than 11.8 million cases of infection since the pandemic began.

State officials are confident they can speed up the vaccine campaign as they add more doses to their arsenal.

The country is currently using two vaccines - Indian-made doses of Astrazeneca and a home-grown one from Bharat Biotech.

It may soon approve Russia's Sputnik V vaccine.

Health authorities hope to immunize at least 300 million people by August.

A temporary hold has also been put on all major exports of the AstraZeneca shot made by the Serum Institute of India.

From April, India will expand its vaccine campaign from the elderly and vulnerable to everyone over the age of 45.

Asli Bai Sayat, 72, had to travel for two hours on a camel cart to get her first COVID-19 vaccine shot in the Indian desert state of Rajasthan, but she may not have to go so far for the follow-up dose.

After a slow start, India is picking up the pace of its immunisation campaign, simplifying the process, opening more vaccination centres and turning to social media as it tries to head off a new surge in infections that has brought the highest tallies of daily cases and deaths in months.

More than 3.2 million people got vaccinations on a single day last week, one of the world's highest rates, and health authorities around the country are calling for more doses as demand picks up and supplies in some places dwindle.

"I came with my husband from about 30km to get the first dose," Sayat, wearing a red-and-beige traditional dress with a walking stick by her side, told Reuters in the town of Shri Dungargarh.

"It's hard to travel each time at this age but we have no choice."