Population
Population — global distribution · migration · demographics
12 min read · Updated 2026-05-25
What is World population?
World population was about 8.1 billion in 2024, having passed 8 billion on 15 November 2022, and is projected to peak near 10.3 billion around 2086. India overtook China as the most populous country in April 2023. Global total fertility is about 2.3 against a replacement level of 2.1, and 281 million people are international migrants.
The story
14 April 2023. The United Nations Department of Economic and Social Affairs (UN-DESA) issues a one-line press release: "India has overtaken China as the most populous country in the world." It happened quietly — no census reading, no fanfare, just a statistical crossover after 47 years of UN data series. China's population began declining in 2022 for the first time since the famine year of 1961. India's continues to grow, projected to peak at ~1.7 billion around 2064.
8 billion — the world hit it on 15 November 2022. It took us 127 years to go from 1 billion (1804) to 2 billion (1928) — and only 12 years for the latest billion (2010 → 2022). But the growth rate has been falling since 1968 (peak 2.1%/yr); today it's 0.9%/yr and falling. By 2086, the UN projects world population peaks at ~10.3 billion and then declines for the first time in modern history.
The story has flipped. The 20th century anxiety was too many people — Paul Ehrlich's Population Bomb (1968), China's One-Child Policy (1979), India's Emergency-era sterilisation. The 21st century anxiety is not enough working-age people — Japan, Italy, Germany, South Korea, China, soon India. Demography is no longer about feeding the next billion; it's about who pays for the pension of the last billion.
Why this matters for UPSC
Syllabus location: GS-I — World Geography (population distribution, migration, demographics); GS-I — World Society. Asked 3-4 times in Prelims over the last decade — top-populous, demographic dividend, refugee hotspots. Mains 2017 (ageing societies), 2020 (international migration), 2023 (population census policy). Very high contemporary salience.