NEW DELHI -- India has started shipping Covid-19 vaccines to multiple cities, four days ahead of a nationwide inoculation drive.

The first consignment of vaccines developed by the Serum Institute of India left the city of Pune on Tuesday. The vaccines rolled out from Serum Institute of India’s facility in temperature-controlled trucks to the city’s airport, from where they were loaded into private air carriers for distribution all over the country.

Civil aviation minister Hardeep Singh Puri called the shipping of vaccines a “momentous mission.”

Beginning Saturday, India will start the massive undertaking of inoculating an estimated 30 million doctors, nurses and other front-line workers. The effort will then turn to inoculating around 270 million people who are either older than 50 or have secondary health conditions that raise their risks of dying from Covid-19.

The first vaccine shipments contain the Covishield vaccine made by the Serum Institute and developed by Oxford University and AstraZeneca.

India's drug regulator has also approved for emergency use a homegrown vaccine, Bharat Biotech’s Covaxin. Medical groups and others have raised concern about the drug being approved with scant evidence of its effectiveness. It’s still unclear when and where Covaxin will be distributed.

India has the second-most Covid-19 infections in the world, after the US. It has confirmed more than 10.4 million cases and over 150,000 deaths. (AP)