Health Minister Mansukh Mandaviya will launch a song and an audio-visual film at the Mughal-era Red Fort in New Delhi around noon to "celebrate the landmark milestone", his ministry said.
The country has already injected 998.5 million doses, nearly 90% of them the AstraZeneca vaccine produced locally by the Serum Institute of India.
"I appeal to all unvaccinated Indians to quickly get their shots and contribute to our historic golden vaccination journey," Mandaviya said on Twitter.
The government wants all of India's 944 million adults to get vaccinated this year. As of now 75% of them have got at least one dose and 31% have had two.
India has so far reported 34.1 million COVID-19 cases and more than 452,000 deaths, most during a second wave of infections of the Delta variant that surged through the country between April and May.