Population at a glance

In 2023, India overtook China to become the world's most populous country. About 17 per cent of all the world's people are Indians: roughly one in every six.

The world's population grew from 2.5 billion in 1950 to 8.2 billion in 2025. It is expected to reach 9.7 billion by 2050.

Why such fast growth? The chapter's first answer may surprise you: better healthcare let people live longer.

A population grows when more are born or when fewer die. From the 1950s, fewer people dying did much of the work.

That was a time of big medical advances:

• antibiotics;
• vaccines;
• oral rehydration solution (ORS, for diarrhoea);
• cleaner water and sanitation for more people;
• far fewer children dying of malaria and diarrhoea.

But growth is now slowing down. The United Nations expects world population to peak at about 10.3 billion in the mid-2080s, and then slowly fall as birth rates drop.

It is different in each country:

• China, Japan and Italy: population already shrinking;
• India: still growing, for now;
• Nigeria and Ethiopia: growing fast.

India's own numbers:

• 1951: 361 million;
• 1981: 683 million;
• 2011: 1,210 million;
• 2025: 1,460 million.

That is about four times in 75 years.

People are not spread evenly across the world. Of the 8.2 billion people in 2025, Asia has 4.8 billion and Africa 1.5 billion. Together they hold most of humanity.