
Two “population billionaires”, China and India, face divergent demographic futures
The latest estimates and projections of global population from the United Nations, indicate that China will soon cede its long-held status as the world’s most populous country. In April 2023, India’s population is expected to reach 1,425,775,850 people, matching and then surpassing the population of mainland China (figure 1). India’s population is virtually certain to continue to grow for several decades. By contrast, China’s population reached its peak size recently and experienced a decline during 2022. Projections indicate that the size of the Chinese population will continue to fall and could drop below 1 billion before the end of the century.
Censuses are key sources of information about population size and characteristics
Both China and India conduct regular population and housing censuses to enumerate and document their national populations, and both countries use the information obtained to inform their development planning. In China, the most recent census was taken in November 2020. More than a decade has passed since India’s most recent census in 2011. India’s planned 2021 census was delayed due to challenges associated with the COVID-19 pandemic and is now scheduled for 2024. To estimate and project the size of the Indian and Chinese populations for subsequent years after their last censuses, the United Nations relies on information about levels and trends in fertility, mortality and international migration obtained from vital records, surveys and administrative data (United Nations, 2022b). Uncertainty associated with the resulting estimates and projections implies that the date on which India is expected to surpass China in population size is approximate and subject to revision as more data become available.Current population trends in China and India are determined largely by fertility levels since the 1970s

Population policies in China and India had different impacts
Many factors contributed to falling birth rates in China and India, but the relative contributions of each remain a matter of debate (Bongaarts and Hodgson, 2022). During the second half of the twentieth century, both countries made concerted efforts to curb rapid population growth through policies that targeted fertility levels. In China, the most notable policies were the “later, longer, fewer” campaign of the 1970s, which promoted later marriage, longer intervals between births and fewer children overall, as well as the stricter “one-child” policy, in effect from 1980 until 2015, which limited couples to one or two children with some exceptions (Wang and others, 2016). These policies, together with investments in human capital, changing roles for women and other factors, contributed to China’s plummeting fertility rate in the 1970s and to the more gradual declines that followed in the 1980s and 1990s. India also enacted policies to discourage the formation of large families and to slow population growth, including through its national family welfare programme beginning in the 1950s. However, under India’s federal structure, state governments were able to set their own policy priorities, resulting in varied impacts across different parts of the country. In Kerala and Tamil Nadu, where state governments emphasized socio-economic development and women’s empowerment, fertility declined earlier and at a more rapid pace, falling below the replacement level two decades before the country as a whole. Those states that invested less in human capital, especially for girls and women, experienced slower reductions in fertility, despite controversial mass sterilization campaigns and other coercive measures in some locations (Gupte, 2017; May 2012). India’s lower human capital investment and slower economic growth during the 1970s and 1980s, contributed to a more gradual fertility decline compared to China and, consequently, to more rapid and persistent population growth.Population ageing echoes historical declines in fertility
The ageing of human populations is an inevitable consequence of the demographic transition. Both China and India are experiencing a shift in their populations towards older ages. In fact, most countries are experiencing some degree of population ageing, though with important differences that stem from the varied pace and timing of the demographic transition (United Nations, 2017b, 2023).
Both China and India must prepare for growing numbers of older persons
The number of older persons is growing rapidly in both China and India. This growth is linked to increasing numbers of births around the middle of the last century, as those cohorts are now reaching older ages, and to falling mortality risks that allow more people to survive to advanced ages. Between 2023 and 2050, the number of persons aged 65 or over is expected to nearly double in China and to more than double in India, posing significant challenges to the capacity of healthcare and social insurance systems.