The global health group's Technical Advisory Group (TAG) issued the final decision.
The WHO, in a tweet, said: "WHO has granted emergency use listing (EUL) to Covaxin, developed by Bharat Biotech, adding to a growing portfolio of vaccines validated by WHO for the prevention of Covid 19".
The source said that Prime Minister Narendra Modi had pushed for Covaxin approval at G20 meet with WHO Director General Dr Tedros Adhanom Ghebreyesus.
The emergency listing got delayed as the TAG sought some additional information from vaccines manufacturers for final risk assessment.
The TAG last met on October 27 and had agreed upon to conduct the final risk assessment after receiving additional data from the manufacturer. Bharat Biotech was expected to submit the additional data by this weekend.
Covaxin, which was co-developed by Hyderabad-based Bharat Biotech, in collaboration with the government's Indian Council of Medical Research (ICMR), was granted emergency authorisation in the country in January.
It has demonstrated 77.8 per cent effectiveness against symptomatic Covid-19 and 65.2 per cent protection against the new Delta variant. Bharat Biotech said that it concluded the final analysis of Covaxin efficacy from Phase 3 trials.
The global health body has so far approved Covid-19 vaccines of Pfizer-BioNTech, AstraZeneca-SK Bio/Serum Institute of India, Johnson 7 Johnson - Janssen, Moderna, and Sinopharm for emergency use against Covid-19.