Indian airlines have started delivering batches of Covid-19 vaccines across the country, getting ready for the launch of a campaign to offer shots to 1.3 billion people in what officials call the world’s biggest vaccination drive.

Authorities hope to inoculate 300 million high-risk people over the next six to eight months. Vaccinations are scheduled to begin on Saturday.

First to get the vaccine will be 30m health and other front-line workers, followed by about 270m people aged over 50 or deemed high-risk.