[Representational Image]Reuters

India has surpassed China to become the world's most populous country with a total population of 1.32 billion, according to University of Wisconsin-Madison academic Yi Fuxian. The academician's claim has perturbed many demographers.

Yi has campaigned against Beijing's draconian family-planning laws for years. The academician, speaking at a news conference in Beijing, said he was certain that over the last 26 years Chinese statisticians had overestimated the country's population by about 90 million. He claimed China had partly inflated rates of fertility in the country, if adjusted, the actual figures of the country's population would be 1.29 billion.

"I think the real number is 1.29 billion but the government thinks it is 1.38 billion," Yi said. "India is maybe 1.32 billion right now," he said during an interview with the Guardian.

Yi said that his findings show that China should scrap all controls on the civilians decision to have children, to soften the blow of a looming ageing crisis in the country. Beijing had replaced its notorious one-child policy with two-child policy in 2015.

The academician said he hoped his controversial finding would initiate a debate over China's demographic timebomb which he called the country's "number one problem". His claims, however, have perplexed scholars in India and China who consider his findings sceptical.

People walking on the Great Wall of ChinaReuters

A leading demographer from the University of California, Wang Feng, called Yi's findings sensational, very sloppy and based on highly politicised back-of-the-envelope calculations, the Guardian reported.

"He's a person with a political agenda and [who has been] a consistent critic of the Chinese government's policy ... [so] his numbers should not be taken at face value."

"I don't disagree with his general criticisms [of China's birth control policy]," Wang added. "But ... we have to speak from facts or we just speak from conjecture ... I think he just wants to make a point to say that fertility is very low in China, the government has inflated the birth numbers, and [therefore] China should have no birth control policy."

Meanwhile, Indian demographers did not appear to agree with Yi's findings either.

"China is still the most populated, but India will overtake them by 2025," said Laushram Ladu Singh, a population researcher at Mumbai's International Institute for Population Sciences.