The United Nations has announced that India is on track to become the world's most populous nation, surpassing China by the middle of this year.

The UN Population Fund said in a report on Wednesday that India's population is estimated at 1.4286 billion as of the end of June. The figure is 2.9 million more than China's 1.4257 billion at that time.

The UN earlier projected that India's population will rise to 1.668 billion in 2050. Declining infant mortality rates in the country are likely to play a role.

The report also shows the population will rise rapidly in Egypt, Ethiopia, Nigeria, Tanzania, the Democratic Republic of the Congo, Pakistan and the Philippines, and they will account for half the global population's increase by 2050.

On the other hand, the report says two-thirds of people on the planet are living in regions with low fertility.

It cites extreme changes in demographics, with the population booming in some regions and declining in others.