Cars line up outside a shopping mall in India's capital New Delhi where a drive-thru clinic has been set-up to administer Covid-19 vaccines. Demand is far outstripping supplies for jabs in India, with only 3.5 percent of the population fully vaccinated.

"We’re vaccinating a little more than we were about 10 days ago, two weeks ago. We’ve crossed three million per day," says Gautam Menon, professor of physics and biology at India’s Ashoka University.