India overtakes China to become world’s most populous country

India has overtaken China as the world's most populous country, according to UN population estimates, the most significant shift in global demographics since records began.

According to the UN's projections, which are calculated through a variety of factors including census data and birth and death rates, India now has a population of 1,425,775,850, surpassing China for the first time.

It is also 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 bring the country's booming birthrate under control, including the introduction of a one-child policy in the 1980s. This included fines for having extra children, forced abortions and sterilisations. While initially highly effective in controlling the population, these policies became a victim of their own success, and the country is now grappling with an ageing population in steep decline, which could have severe economic implications.

Part of the problem is that because of a traditional preference for boys, the one-child policy led to a massive gender imbalance. Men now outnumber women by about 32 million. "How can the country now shore up birth rates, with millions of missing women?" asks Mei Fong, the author of One Child, a book about the impact of the policy.

Recent policies introduced in China trying to incentivise women to have more children have done little to stimulate population growth. Women still have only 1.2 children and the population is expected to fall by almost 10% in the next two decades. According to projections, the size of the Chinese population could drop below 1 billion before the end of the century.

In India, the population has grown by more than a billion since 1950. Though growth has now slowed, the number of people in the country is still expected to continue to rise for the next few decades, hitting its peak of 1.7 billion by 2064. Today on average 86,000 babies are born a day in India compared with just 49,400 in China.