Updates to United Nation Population Division data has moved the date at which India would overtake China as the world's most populous nation forward to 2023. Demographers have long agreed that the shift would happen, but disagreed on when. As China's population started to grow much more slowly in recent years and even shrunk for the first time in decades in 2022, the change is now coming faster than many expected. As recently as 2019, it had been predicted for 2027.
Looking at population estimates that the UN has published for July 1, 2022 and July 1, 2023, the changeover should occur on April 1. Website World Population Review, using their own live population counter, meanwhile says it already happened and that around 3 million more people now live in India than in China. Currently, India gains around 11.5 million people in a year, a number that is still rising, but not for much longer.
By 2100, it's estimated that the planet will have to sustain 10.3 billion people. Between now and the middle of the current century, India is expected to show the biggest absolute population increase. Other countries where a lot of people will be added to the world's population in that time period will be Nigeria, the Democratic Republic of the Congo, Ethiopia and Tanzania.