We have become used to China as the world's most populous nation, but a combination of the one-child policy and urbanisation will see it make way for India in a few years.

At the end of last year, China's population was 1.37 billion. After it peaks in 2025 at 1.41 billion, it is expected to decline to 1.3 billion in 2050, according to Zhang Juwei, director of the Institute of Population and Labour Economics at the Chinese Academy of Social Sciences.

“These projections are part of the background reports we submitted for China’s leadership to consider when it designs its new national five-year plan,” said Zhang.

He was quoted by the China Daily newspaper and was heading a team of Chinese experts at a two-day seminar on economic restructuring and changing employment structures in Brussels last week.

Zhang says the labour supply will remain roughly stable until 2030 despite the challenges of an ageing population and low-fertility levels. He and his team predict that labour supply will range between 14.93 million and 16.98 million people every year from 2013 to 2030, with the number of graduates joining the workforce growing steadily.

"We believe China's demographic changes, even amid the challenges, can sustain at least 10 years of medium-speed growth if we have sensible policy options," he said. Lin Bao, a research fellow at the same institute, says these kinds of challenges could lead to the one-child policy being "totally relaxed".

The policy has been relaxed to allow those with one child and some urban residents to have another child. Some commentators believe the one-child policy could be rolled back further in the forthcoming five-year plan, to reflect the growing challenges in demographic terms. “We have relaxed the family policy by allowing those only-child couples to give birth to a second child but, so far, this policy has not achieved the desired results. So I believe that our family planning policy will be totally relaxed soon,” Lin said.