World Population Day: Know all about the world’s top 5 populous countries  

The global population which reached 7 billion people in 2011, is now a staggering 8.04 billion and as per the United Nations, is expected to grow to 8.5 billion in 2030, 9.7 billion in 2050 and 10.9 billion in 2100.

A rise in the number of people surviving to the reproductive age, changes in fertility rates due to shifting social-economic trends, more urbanization and increase in migration are reasons that have driven the growth.

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Factors such as rapid urbanisation, decline in fertility rates and life expectancy, which have determined the population rates of countries have also had far-reaching consequences on the economies of these countries and their income distribution, poverty and social protections.

On the occasion of World Population Day, here’s a glance at the most populated countries of the world and what has led to a shift in their demographics over the decades:

India: How it surpassed China in population  

India’s population in April 2023 crossed the 1.4 billion-mark to surpass China’s in being the largest populous country in the world.

Experts attribute the growth to a phenomenon called ‘demographic momentum’, as part of which a country’s population continues to grow despite a decline in fertility rate because a large proportion of the population is still entering its reproductive years and wants to have children.

In fact, India’s growth rate started to decline post 1990s after remaining steady at 2.2 per cent for 30 years between 1971 and 1991. It was 1.6 in 2011.

The United Nations Population Fund (UNFPA) says India’s population in 2021 was 1,393.4 million with an average annual rate of change of population of 1 per cent.

India’s current fertility rate now stands at 2.0 births per woman, just below the replacement threshold of 2.1, the level needed to stabilise a population in the absence of migration.

Also read: US: Immigration drove white, Asian population growth last year

Experts say the demographic momentum in India is expected to continue for another three decades before stabilising. Its population, as per one projection, is expected to peak by 2048 before declining. They say some projections estimate India’s population to decline to 1.1 billion by 2100.

India’s upward move on the population scoreboard has also been possible due to a drastic fall in China’s population – again a result of its restrictive policies over the years.

The Chinese population is estimated to drop below 1 billion before the end of the century, India’s population is estimated to grow for many more decades.

A report by the United Nations says that while China, which in the 1970s had under six births per woman – same as India – managed to bring the birth rate to three births per woman in a span of seven years, it took India over three and a half-decades to achieve the same feat.

While a country’s average fertility rate – children per woman – should be 2.1 for the population to sustain itself and grow, China in 2022 recorded 1.2 births per woman, the lowest in the world.

China: What led to its population decline?

Restrictive policies imposed by the Chinese government including the one-child policy in the 1980s, as well as changing attitude towards marriage and family, gender bias like more pressure on the woman on raising children, discrimination at work for working mothers or pregnant women, and preference of young couples to go childless, have been attributed as reasons that have led to a decline in the growth rate.

China recorded a fall in its population to 1.411 billion in 2022, down by around 850,000 people from 2021.

Watch | Beijing’s population declines for first time in two decades; here’s why

Its current population is now 1,456,052,951, around 18.7 per cent of the total world population.

If the growth rate continues to fall, China faces the risk of losing its status as the second-largest economy in the world as the percentage of the population at the ages 25-64 will peak in the next coming years, shrinking its youth labour force and leaving the country with an aging workforce.

India on the contrary, will see a rise in the number of adults in the working age in the next few years, leading to faster economic growth.

United States: Asians, migration boost fertility rate  

The United States, the third-most populated country in the world, in 2023 witnessed a 0.5 per cent growth rate, up from the growth rate of 0.38 per cent in 2022.

The country’s current population stands at 336.9 million, 4.25 per cent of the world’s population.

As per the US Census Bureau, while restrictions on immigration, and dip in fertility rate had kept the growth rate stagnant, the COVID-19 pandemic worsened it, leading the country to record the least growth in 120 years in 2019-2020. Between July 2019 and July 2020, the country’s population grew by just 0.35 per cent.

Latest population figures released by the US Census Bureau said, an expansion in Asian population, and births outpacing deaths in Hispanic, African Americans and Hawaiian population have helped improve the population growth rate of the country post COVID.

Reports said without immigration, the white population would have declined by more than 85,000 people in 2022.

Also read: Rising sea levels can lead to mass exodus of entire populations on biblical scale: UN chief

According to Worldometer, the country’s population, riding on a fertility rate of 1.78 births per woman, is expected to grow to 379,419,102 by 2050.

Indonesia: A relatively young population

The Asian country which has a population of 282,483,220, as per Worldometers, has a fertility rate of 2.32 births per woman.

The country has a relatively young population with almost 56.4 per cent concentrated in urban areas. Even though governments have been putting effective family planning programmes in place, the country’s average population growth has been 1.1 per cent for the decade ending 2020.

Indonesia’s population, which was 2.73 billion in 2021, has grown by 0.64 per cent in 2022 and 0.74 per cent in 2023 to reach the current number. It is further projected to grow 3.30 billion by 2050.

Pakistan: ‘Dangerous population boom’

The fifth-most populated country in the world, Pakistan is witnessing an exponential population boom and may surpass the US to jump to the third rank by 2050.

Pakistan’s current population stands at 234.5 million, 2.83 per cent of the world’s population. The country has a fertility rate of 3.55 births per woman and the population is expected to touch 338,013, 196 by 2050.

Experts say the high population has been a chief reason behind poor healthcare, education and unemployment rate in the country. On the other hand, the anticipated boom raises concerns about human and economic development, poverty, food security, water crisis and climate change.

Experts say, while several countries in Asia have achieved significant and sustained economic growth through economic reforms and programmes, especially in the areas of family planning, girls’ education and economic empowerment of youth, Pakistan has failed to do so due to absence of political will.

Even as Pakistan’s working age population – between 15 to 64 years – is expected to reach its peak by 2050, the country has little time to use them to further its economic goals.

According to the United Nations Population Fund, around 89 million people or 34.4 per cent of the population faces the danger of slipping below the poverty line by 2030 if the government fails to employ corrective measures.

The other five countries in the most-populated list are Nigeria (222.6 million), Brazil (217.1 million), Bangladesh (169.7 million), Russia (146.1 million) and Mexico (133.1 million).