India has overtaken China to become the world's most populous nation, marking a historic demographic shift that is already reshaping global economic growth, labour markets and geopolitical influence.

According to the United Nations World Population Prospects 2024 , India's population is projected to continue growing for several decades, while China's is expected to decline steadily as the effects of low birth rates and population ageing intensify.

The latest UN projections highlight a dramatic reversal in demographic fortunes between the two Asian giants, which together account for more than one-third of humanity.

UN estimates indicate that India's population has risen from approximately 201 million in 1800 to around 1.46 billion today , making it the world's largest country by population .

Under the UN's medium-fertility scenario, India's population is projected to reach roughly 1.68 billion by 2050, before gradually declining to around 1.51 billion by the end of the century.

The growth has been driven by improvements in healthcare, declining mortality rates and a relatively young population. India currently has one of the world's largest working-age populations, a demographic advantage economists often refer to as a "demographic dividend."

However, experts note that turning population growth into economic prosperity will depend on creating sufficient jobs, expanding education and improving infrastructure.

China's demographic story is moving in the opposite direction.

The UN estimates China's population grew from around 330 million in 1800 to a peak of more than 1.4 billion in recent decades. Yet falling fertility rates, rising living costs and longer life expectancy have contributed to a sustained population decline.

Under current projections, China's population is expected to fall from about 1.41 billion today to 1.26 billion by 2050, before shrinking further to approximately 633 million by 2100.

The decline reflects one of the most significant demographic transitions in modern history. China's fertility rate remains well below the replacement level of 2.1 children per woman despite policy efforts aimed at encouraging larger families.

Around the city, supporters gathered near the Monument to the Revolution wearing Mexico jerseys and waving national flags. Others purchased team shirts from street vendors despite growing concerns over merchandise restrictions.

For some fans, access to the tournament has become increasingly difficult.

"It's a World Cup that Mexico isn’t really invited to, mainly because of the restrictions. As Mexicans, we try to express our identity and show our pride, but unfortunately, right now the only ways to watch are through paid television," said Mexico City resident Aldo Nunez.

At Estadio Azteca, where Mexico is scheduled to face South Africa in the opening match on Thursday, average ticket prices have reportedly climbed to around $1,300.

Street vendors also voiced frustration over FIFA's rules on merchandise sales.

"We've been saving money so we could invest in merchandise. And now FIFA is saying that we can't sell anything from Mexico [...] Most of us don't agree with it," said vendor Jazmin.

"They're fining businesses for showing the matches in restaurants, and that’s not fair. People go out to dinner so they can enjoy a game," she continued.

Questions also remain over fan events planned around the tournament.

Due to ongoing blockades by the teachers' union CNTE near Estadio Azteca and the Zócalo, President Claudia Sheinbaum said it remains unclear whether the World Cup opening fan festival can be held in the city's main square.

The union is demanding higher wages and changes to pension policies , demands the government says are financially unworkable.

Visitors arriving for the tournament have also expressed concern.

"I just found out that a police officer said everything may be canceled tomorrow," said Deyanira, a Mexican resident of Germany who travelled to Mexico City for the World Cup.

"So I don’t know. I am a bit disappointed and surprised by the organisation."

"Now I arrive in my country and see a bit of chaos: marches, protests , restrictions, and everything is extremely expensive. So it's definitely a different World Cup," she added.

The 2026 FIFA World Cup begins on June 11 in Mexico City and will be hosted across Mexico, the United States and Canada in an expanded 48-team tournament.