India is expected to surpass China to become the world's most populous nation by 2022, said the United Nations.
China and India remain the two largest countries in the world, each with more than 1 billion people, representing 19 and 18 per cent of the world's population, respectively.
"But by 2022, the population of India is expected to surpass that of China," said the report 'World Population Prospects: The 2015 Revision', released by the UN.
Currently, among the ten largest countries in the world, one is in Africa (Nigeria), five are in Asia (Bangladesh, China, India, Indonesia, and Pakistan), two are in Latin America (Brazil and Mexico), one is in Northern America (USA), and one is in Europe (Russian Federation).
Of these, Nigeria's population is growing the most rapidly.
Consequently, the population of Nigeria is projected to surpass that of the US by about 2050.
By 2050, six countries are expected to exceed 300 million: China, India, Indonesia, Nigeria, Pakistan, and the USA, the report said.
A significant ageing of the population in the next several decades is projected for most regions of the world, starting with Europe where 34 per cent of the population is projected to be over 60 years old by 2050.
In Latin America and the Caribbean and in Asia, the population will be transformed from having 11 per cent to 12 per cent of people aged over 60 years today to more than 25 per cent by 2050.
Africa has the youngest age distribution of any major area, but it is also projected to age rapidly, with the population aged 60 years or over rising from five percent today to nine per cent by 2050.
The current world population of 7.3 billion is expected to reach 8.5 billion by 2030, 9.7 billion in 2050 and 11.2 billion in 2100, the report said.
(With inputs from PTI)