India is likely to approve Oxford/AstraZeneca's coronavirus vaccine for emergency use by next week after Serum Institute of India (SII) submitted additional data sought by authorities, two sources with knowledge of the matter told Reuters on Tuesday.

This could be the first country to give the regulatory green light for the British drugmaker's vaccine as the British medicine regulator continues to examine data from the trials.

India, the world's biggest vaccine-making country, wants to start inoculating its citizens next month and is also considering emergency use authorisation applications for vaccines made by Pfizer Inc and local company Bharat Biotech.

Getting vaccines to the world's second-most populous country with one of the highest infection rates will also be a big step in the battle against the pandemic.

The AstraZeneca-Oxford shot is considered vital for lower-income countries and those in hot climates because it is cheaper, easier to transport and can be stored for long periods at normal fridge temperatures.

India's Central Drugs Standard Control Organization (CDSCO) first reviewed the three applications on December 9 and sought more information from all the companies, including from Serum Institute of India (SII), which is making the AstraZeneca shots.

SII, the world's biggest vaccine manufacturer, has now provided all the data, the two sources said. The authorities were still waiting for more details from Pfizer, a government health adviser told a news briefing on Tuesday, while one of the sources said additional information was expected from Bharat Biotech.