These will be the world's 10 biggest cities in 2050 — and you probably haven't heard of some of them

• Rebecca Harrington, Tech Insider

• Feb. 18, 2016, 10:55 AM

REUTERS/Nicky Loh

The human population is growing at an alarming rate. By 2050, there will be almost 10 billion people on the planet. 

We've been hearing this for years, but where is the most growth happening? 

Today, Tokyo is the most populous city in the world, with about 38 million residents.

Currently, just one of the 10 most populous cities in the world is in Africa (Cairo), and only two (Sao Paulo and Mexico City) are in Latin America. But in the next three decades, that's going to change. 

Based on population growth models, the Global Cities Institute at the University of Toronto projects these will be the 10 biggest cities in 2050. 

10. Mexico City, Mexico: 24.3 million people

Alfredo Estrella/AFP/File

People participate in a "Zombie Walk" at the Revolution Monument in Mexico City.

9. New York, United States: 24.8 million people

Lucas Jackson/REUTERS

Revelers take part in New Year celebrations in New York's Times Square, January 1, 2010.

8. Karachi, Pakistan: 31.7 million people

Akhtar Soomro/REUTERS

Supporters of the political party Pakistan Tehreek-e-Insaf take part in a rally near the mausoleum of Mohammad Ali Jinnah in Karachi, Pakistan, on December 25, 2011.

7. Tokyo, Japan: 32.6 million people

Thomas Peter/REUTERS

Runners fill the street at the start of the Tokyo Marathon in Tokyo, February 22, 2015.

6. Lagos, Nigeria: 32.6 million people

Akintunde Akinleye/REUTERS

People crowd on a road near Balogun market to shop, a day before Christmas in Nigeria's commercial capital, Lagos, December 24, 2012.

5. Kolkata, India: 33 million people

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Hindu devotees prepare to receive rice as offerings being distributed by the temple authority on the occasion of the Annakut festival in Kolkata, India, on October 24, 2014.

4. Kinshasa, Democratic Republic of the Congo: 35 million people

Media Coulibaly/REUTERS

Fans climb a scoreboard to watch an African Cup of Nations qualifying soccer match between Ivory Coast and Democratic Republic of Congo in Kinshasa, on October 11, 2014.

3. Dhaka, Bangladesh: 35.2 million people

Ashikur Rahman/REUTERS

People crowd on top of a train entering the Dhaka airport rail station September 24, 2015, as thousands of Bangladeshi Muslims head home to celebrate Eid-al-Adha.

2. Delhi, India: 36.2 million people

Adnan Abidi/REUTERS

Indian Prime Minister Narendra Modi performs yoga with others to mark the International Day of Yoga, in New Delhi, India, on June 21, 2015.

1. Mumbai, India: 42.4 million people

Danish Siddiqui/REUTERS

Devotees try to form a human pyramid to break a clay pot containing curd during the celebrations to mark the Hindu festival of Janmashtami in Mumbai, on August 10, 2012.

Mumbai won't be No. 1 for long. 

The Global Cities Institute projects that Kinshasa, in the Democratic Republic of the Congo, will be the most populous city in the world by 2075, and that by 2100, it will be surpassed by the 88 million future residents of Lagos, Nigeria.