All the people India's rise is accompanied by China's contraction

India has overtaken China as the most populous country, the most significant shift in global demographics since records began more than 70 years ago

- Hannah Ellis-Petersen

According to the UN's projections, which are calculated using factors including census data and birth and death rates, India's population is 1,425,775,850. It is the first time since 1950, when the UN first began keeping global population records, that China has been knocked off the top spot.

China's population decline follows decades of strict laws to curb the birthrate, including the introduction of a one-child policy in the 1980s, which included fines for having extra children, forced abortions and sterilisations. While highly effective, these measures became victims of their own success, and the country is grappling with an ageing population in steep decline, which could have severe economic implications.

The one-child policy also led to men now outnumbering women by about 32 million. "How can the country now shore up birthrates, with millions of missing women?" asked Mei Fong, the author of One Child, a book about the policy.

Recent efforts to encourage women to have more children have done little and the population is expected to fall by almost 10% in the next two decades.