New Delhi, July 11 -- India and Nigeria will host the two fastest growing populations over the next three decades, with India adding 273 million people and Nigeria 200 million by 2050, the rapid pace fuelled by vastly different factors, according to the United Nations World Population Prospects 2019 report.

India will overtake China to become the world's most populous country in 2027, according to the report. The world's population is projected to increase by 2 billion people, from 7.7 billion now to 9.7 billion in 2050, according to the report.

While India's population will increase because of a large cohort of young people who will enter their reproductive age over the next three decades, which will add "population momentum" even if bir...