India is set to overtake China to become the most populous country in the world by the middle of this year, data released by the United Nations shows.

India's population is pegged to reach 1,428.6 million against China's 1,425.7 million.

This shows India will have 2.9 million more people than its Asian neighbour.

The Asian giants have more than 1.4 billion people each, and have accounted for more than a third of the global population for over 70 years.

India's population number, however, is an estimate since there has been no Census in the country after 2011.

Also, the UN says their estimate does not include the population of China's two Special Administrative Regions - Hong Kong and Macau - and the island of Taiwan, which Beijing sees as a breakaway province to be unified with the mainland one day. But Taiwan sees itself as distinct from the Chinese mainland, with its own constitution and democratically-elected leaders. 

In November, the global population crossed 8bn. But experts say growth is not as rapid as it used to be and is now at its slowest rate since 1950.

Both India and China have seen declines in their fertility rates. In China, the population started declining last year, despite the country abandoning its one-child policy in 2016 and introducing incentives for couples to have two or more children.

In India too, fertility rates have fallen substantially in recent decades from 5.7 births per woman in 1950 to 2.2 births per woman today.