A report published in British journal The Lancet reckons India’s working population will surpass China’s in the mid-2020s.
India’s gross domestic product (GDP) growth rate could slow in the second half of this century as its population declines from a peak in 2048 to a 32 per cent lower level by 2100.
The number of its working-age adults (aged 20-64) could fall from about 762 million in 2017 to around 578 million in 2100.
These are among the projections in an analysis published by The Lancet, an internationally respected British publication on health affairs.
The journal’s Editor-In-Chief Richard Horton said: “This important research charts a future we need to be planning for urgently.
"It offers a vision for radical shifts in geopolitical power, challenges myths about immigration, and underlines the importance of protecting and strengthening the sexual and reproductive rights of women.”
He added: “The 21st century will see a revolution in the story of our human civilisation.
"Africa and the Arab World will shape our future, while Europe and Asia will recede in their influence. By the end of the century, the world will be multipolar, with India, Nigeria, China, and the US the dominant powers.”
The report contradicts an earlier forecast by the United Nations Population Division of “continuing global growth”.
A shrinking workforce, and therefore, lower tax revenues together with an ageing population, will put enormous pressure on health and social care systems.
India’s population is pitched to rise to 1.6 billion in 2048 - up from 1.38 billion in 2017 - followed by a diminution to 1.09 billion by 2100.
The country’s total fertility rate (TFR) fell to 2.1 in 2019 or slightly above replacement level. It is envisioned this will continue to fall, reaching a TFR of 1.29 in 2100.
Despite the prognosis of shrinkage in working-age adults, it is estimated India will still have the largest workforce in the world in 2100.
The report reckons India’s working population will surpass China’s in the mid-2020s.
The Chinese working people numbered 950 million in 2017; this could diminish to 357 million in 2100.
India, ranked 7th among nations with the largest total GDP in 2017, is computed to be 3rd in 2100.
India is expected to have the second-largest net immigration in 2100, with half a million more people immigrating than emigrating.
It is also estimated to have one of the lowest life expectancies in 2100 - 79.3 years, albeit up from 69.1 years in 2017.
Seattle-based Institute for Health Metrics and Evaluation Professor, Stein Emil Vollset, first author of the paper, stated: “The societal, economic, and geopolitical implications of our predictions are substantial.”
He warned: “Responding to population decline is likely to become an overriding policy concern in many nations, but must not compromise efforts to enhance women’s reproductive health or progress on women’s rights.”
The global population is predicted to reach its height in 2064 at approximately 9.7 billion people and then descend to 8.8 billion by the end of the century.
Twenty-three countries could experience a downsizing of 50 per cent in their population, including Japan, Italy, and Spain. Only liberal immigration policies would, thus, maintain optimum population levels and economic growth.
TFR worldwide will steadily decrease from 2.37 in 2017 to 1.66 in 2100.
In Niger, which has the highest fertility rate on earth and where women on average give birth to seven children, the TFR is calculated to dwindle to 1.8 by 2100.
North Africa and West Asia are the only two regions forecast to have a larger population in 2100, compared to 2017.
Population sizes in several parts of Asia are portrayed to wane.
Japan - from 128 million in 2017 to 60 million in 2100.
Thailand - from 71 million to 35 million. South Korea - from 53 million to 27 million. China - from 1.4 billion to 732 million.
The number of children under five years of age could decline 41 per cent by the turn of the century, while there could be sixfold increase in above 80s.
The population contraction, though, is potentially good news to reduce carbon emissions and pressure on food security.
China is set to replace the US in 2035 as the country with the largest total GDP, but the rapid fall in the former’s population from 2050 could mean the US will reclaim the top spot by 2098.