How India will overtake China to become the most populous country

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India is poised to overtake China to become the world's most populous country, according to estimates by the United Nations.

The shift marks a significant milestone for the South Asian nation and will have far-reaching implications for its economy, society and global influence.

The animation below shows how India's population has more than quadrupled from 350 million inhabitants in 1950 to an estimated 1.43 billion people today.

Meanwhile, China's population, which peaked at 1.42 billion in 2021, is gradually declining.

In the following infographic series, Al Jazeera breaks down all the numbers on how this happened and what this means for the rest of the world.

Where do 2.8 billion people live?

India and China have a combined population of 2.8 billion people. That means every third person in the world comes from either of the two Asian countries.

To put that in context, there are more people in India and China than the next 19 most populated countries in the world combined.

The 3D map below shows the population densities of cities across India and China. Areas with large spikes represent heavily populated cities.

China's eastern region, which is rich in agricultural resources, is home to more than 90 percent of the country's population.

Across the border in India, which is about one-third the size of China in terms of land area, most inhabitants are clustered in the northern part of the county.

INTERACTIVE - India-China population map horizontal
(Al Jazeera)
(Al Jazeera)

India's most populous cities

It has been more than 11 years since India conducted its last census, making it difficult to know exactly how many people it has. As of 2011, the South Asian country had 27 cities with populations exceeding one million. Today, that number is likely closer to 50, according to estimates.

New Delhi

India’s most populous city is capital New Delhi, with some 30 million inhabitants across its central city and its surrounding urbanised areas.

If Delhi was a country, it would be the 50th most populous country in the world behind Malaysia, Ghana and Mozambique.

Before and after satellite images below show how the city has more than quadrupled from around seven million inhabitants in 1984 to 30 million today. Drag the slider to the left to see how that city has transformed.

Mumbai

India's second most populous city and the country's busiest port city, Mumbai is home to some 20 million people.

Formerly known as Bombay, the country's financial hub has doubled from some nine million inhabitants in 1980 to 20 million people today.

Kolkata

Located in the eastern part of India near the border with Bangladesh, Kolkata is one of India's largest and most populous cities, with a population of 15 million people.

Home to several universities and research institutions, the country's cultural centre has continued to expand as shown in the before and after satellite images below.

Bengaluru

Bengaluru, also known as Bangalore, is the largest city in the southern Indian state of Karnataka and has a population of around 12 million people.

A technology and commerce hub, often referred to as the "Silicon Valley of India", Bengaluru has more than quadrupled in size over the past four decades.

China's most populous cities

A city's population can be measured by the permanent inhabitants of its administrative boundaries, urban area or metropolitan area.

According to the UN World Urbanization Prospects, which measures urban areas, China's most populous city is Shanghai with some 27 million inhabitants, followed by Beijing with 20 million and Chongqing with 16 million.

Shanghai

Situated at the mouth of the Yangtze River on China's east coast, Shanghai is one of the world's largest shipping hubs and among the most populated cities in the world.

If Shanghai was a country, it would have about the same number of inhabitants as Australia, Cameroon, Venezuela or the entire US state of Texas.

Before and after satellite images below show how Shanghai nearly quadrupled from about seven million inhabitants in 1984 to 27 million today.

Beijing

China's capital, Beijing, derives its name from its location - "bei", which means north, and jing, which means capital.

The ancient city has about the same number of inhabitants as Malawi, Romania, Sri Lanka or the US state of Florida.

The before and after satellite images below show how Beijing has grown from about six million inhabitants in 1984 to some 20 million today.

Chongqing

Also located along the Yangtze River in southwest China, Chongqing has seen a rapid increase in urban population from three million inhabitants in the 1980s to more than 16 million today.

When combined with its large rural population, the megacity is one of the largest in the world with an estimated 30 million inhabitants.

Before and after satellite images below show just how much the city has grown over the past four decades.

How are populations calculated?

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Simply put, a country’s population is calculated using four numbers - births, deaths, immigration (entering the country) and emigration (leaving the country).

When births and immigration exceed deaths and emigration, a country’s population increases; when the reverse happens, its population decreases.

Population growth slowing

While India's population is still growing, the rate of its growth is actually slowing.

In order for a population to replace itself from one generation to the next, without migration, it is generally accepted that every couple should have an average of 2.1 children, where 0.1 makes up for the children who die before reaching adulthood.

The animated graphic below compares India and China's fertility rates, which measure the live births per woman, from 1950 to 2050.

At its peak in 1963, Chinese women had an average of 7.5 children. Today, that number has plummeted to just 1.2.

India's fertility rate has also been steadily declining from nearly six during the 1960s to two children today.

Deaths outnumber births in China

For the first time since 1960, the number of deaths across China has outnumbered births. According to Beijing’s National Bureau of Statistics, the number of births in 2022 was 9.56 million, while deaths stood at 10.41 million.

The animation below compares China's births and deaths over the course of 100 years.

The spike in deaths in 1960 corresponds to the country's worst famine in its modern history under Mao Zedong’s disastrous agricultural policy. In the years immediately following the famine, the number of births reached an all-time high of 33 million in 1963.

Despite China ending its strict “one-child policy” in 2016 and authorising couples to have up to three children in 2021, the policy change has not reversed the demographic decline.

CHINA, SHENZHEN - OCTOBER 14 : Shenzhen became China's first Special Economic Zones (SEZs) and the major city in the south of Southern China's Guangdong Province, north of Hong Kong in Shenzhen on October 14, 2016 in China. (Photo by Frédéric Soltan/Corbis via Getty Images)
The coastal city of Shenzhen, located near Hong Kong, grew from about 30,000 inhabitants in the 1980s to more than 12 million today [Frederic Soltan/Corbis via Getty Images]

India's births also declining

The number of births across India has also been declining since the early 2000s, albeit at a slower rate than China's. Still, at about 23 million births in 2022, there are more people born in India every day (63,000) than anywhere else in the world.

In 2021 and 2022, during the height of the coronavirus pandemic, India recorded 13.3 million births and 12.8 million deaths respectively.

According to UN projections, based on the current trajectory, the number of births and deaths will continue to converge until 2066.

India Population Women in the Workforce
A view of the Dharavi slum in Mumbai, India on March 16, 2023 [Rajanish Kakade/AP Photo]

Aging populations

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Like much of the rest of the world, both China's and India's populations are getting older.

One way to easily visualise this shift in demographics is to look at a country's population pyramid which sorts the population's age and gender. The bottom of the pyramid represents a country's newborns while the top shows its centennials.

The infographic below shows just how much younger India's population is compared with China's. In fact, India has nearly twice as many infants (0-4 year-olds) than China.

At 113 million, there are more 0-4 year olds in India than the entire population of the United Kingdom (67 million), Germany (83 million) or Egypt (110 million).

Another simple measurement to understand a country's population is to look at its median age which represents the age at which half of a given population is older and half is younger.

For most of the 1950s through to the 1970s, both India and China's median ages hovered at about 20 years. However, starting in the 1980s, the two lines started to diverge.

Today, China's median age is 38 while India's is 10 years younger at 28.

The animation below shows how both countries' populations are getting older.

What will the world look like in 2050?

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In 1955, there were 2.8 billion people on Earth. Today, that is the population of China and India alone.

The animation below shows how the world's population is expected to nearly quadruple from 2.5 billion people in 1950 to 9.7 billion people by 2050.

Represented on a cartographic representation, where each country is resized according to its population, the map below shows where each country is expected to rank by 2050.

After India (1) and China (2), Nigeria is expected to become the world's third most populous nation followed by the United States (4), Pakistan (5), Indonesia (6), Brazil (7), Democratic Republic of the Congo (8), Ethiopia (9) and Bangladesh (10).

When the world’s population reached each billion milestone:

The global population has increased eightfold since 1800, from an estimated one billion in 1804 to eight billion in 2022. This growth can largely be attributed to the development of modern medicine and the industrialisation of agriculture, which boosted global food supplies.

  • One billion – 1804
  • Two billion – 1927 (took 123 years)
  • Three billion – 1960 (took 33 years)
  • Four billion – 1974 (took 14 years)
  • Five billion – 1987 (took 13 years)
  • Six billion – 1999 (took 12 years)
  • Seven billion – 2011 (took 12 years)
  • Eight billion – 2022 (took 11 years)
  • Nine billion – 2037* (UN projections)
  • Ten billion – 2057* (UN projections)

While the global population continues to reach new highs, demographic experts have pointed out that the annual growth rate has consistently declined to below one percent.

Based on these projections, the world's population is expected to peak at about 10.4 billion people in the 2080s and remain at that level until 2100.

Source: Al Jazeera