India is on course to top China as the world's most populous country in 2025, the US Census Bureau forecast, potentially changing the dynamics between the Asian giants.

The latest Census Bureau estimates out this week, which are in line with previous studies, predicted that India would have 1.396 billion people in 2025, surpassing China, whose population growth is more modest.

China since 1980 has allowed most women to bear only one child, in a controversial policy aimed at creating a more sustainable population.

The average Chinese woman now has 1.5 children in her lifetime, compared with 2.7 children for the average Indian woman, although the so-called fertility rate has also been declining in India due to rising education and urbanization.

The demographic shift could affect the Asian powers' economies, which are now among the world's fastest. China has enjoyed a stronger growth rate than India as young people flock to manufacturing hubs that pump out exports for the world. But China in coming years will likely face a shrinking labor force and a mass of pensioners.

The US Census Bureau forecast that the ranking of the largest countries would otherwise remain the same in the coming 15 years. The United States whose population is growing more quickly than most wealthy countries, albeit at a slower rate than in recent decades will remain the third largest nation, followed by Indonesia, Brazil, Pakistan, Bangladesh and Nigeria, the figures showed. Countries expected to fall in population rank include Japan, Russia and Germany, whose birth rates have been low for years. AFP