Delhi, Mumbai, and Kolkata among world's top 20 most populous cities

On World Population Day today, we take a look at the 20 most populated cities in the world, and the challenges that need to be addressed.
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World Population Day is observed on July 11 every year. In order to raise awareness about global population issues, the United Nations Development Programme (UNDP) started observing the day from 1989. 

This year, the UN plans to call on all leaders, policy makers, and grassroots organisers to make reproductive rights and health a reality for all.


As population increases across the world, there are a number of problems cities are dealing with, including food, water, and shelter, along with pollution and large quantities of waste. 

Delhi, Mumbai, and Kolkata are among the Indian cities that feature in the list of top 20 most populated cities in the world.

YourStory takes a look at the top 20 populated cities across the world, and what their respective governments are doing to address the problem. 

1. Tokyo

Population: 37,435,191

(Image: Shutterstock)

Tokyo is Japan’s largest metropolis and houses 10 percent of the entire population of Japan.The biggest problem Tokyo faces with regard to its rapidly growing population is its housing crisis. One of the solutions to control Tokyo’s population would be to decentralise Tokyo, which the government is looking into. One way to achieve this would be by moving government-owned companies to the less populated cities and areas of Japan, thereby giving citizens no choice but to relocate.

2. Delhi

Population: 29,399,141

(Image: Shutterstock)

Delhi is the most populated city in India. According to the UN, Delhi might become the most populous city by 2028. Some of the major problems the city faces is the shortage of electricity, improper waste disposal systems, and lack of transport facilities.

3. Shanghai

Population: 26,317,104

Shanghai is one of China’s most commercial cities. Located on the central coast, it is known as the financial hub. Because of the large population, waste disposal systems are minimal. Further, air pollution caused by extensive vehicular emission remains a huge problem.

4. São Paulo

Population: 21,846,507

Sao Paulo is one of the largest metropolitan cities in the world, and the financial capital of Brazil. The biggest problem faced by the city due to its massive population is poverty. Along with this, the city is witnessing unpredictable weather patterns as a result of rapid urbanisation.

5. Mexico City

Population: 21,671,908

Standing in the fifth place among the most populated cities is Mexico City. It is also the most populous city in North America. The major issue faced by the city due to its large population is homelessness, and because of this it has a high demand for housing facilities. The availability of water is another major problem the city is facing. 

6. Cairo 

Population: 20,484,965

Cairo is the capital of Egypt. According to reports, 27.8 percent of Egyptians live below the poverty line, and one child is born every 15 seconds in Egypt. In a 2017 conference, President Abdel Fattah al-Sisi stated: “We have two real challenges facing our country: terrorism and overpopulation,” reports The Guardian

7. Dhaka

Population: 20,283,552

Dhaka, the capital and largest city of Bangladesh, remains one of the most densely populated cities in the world. With a density of 47,400 people per square metre, it is estimated that 1,418 people are added to Dhaka’s population every day.

8. Mumbai

Population 20,185,064

(Image: Shutterstock)

About 60 percent of Mumbai’s population lives in slums, with no clean drinking water, electricity, or gas. The city’s slum rehabilitation authority has been implementing multiple plans to re-home slum residents. Due to overcrowding, Mumbai is also one of the most polluted cities in India, with approximately 7,000 metric tonnes of waste being discarded by individuals every day in the city. The city is so overcrowded that the local trains transport nearly six million people daily, and there has been a number of deaths due to stampede at the stations because of overcrowding.

9. Beijing

Population: 20,035,455

Beijing is one of the most polluted cities in the world, thanks to its population. Local construction, coal burning, and vehicular emissions are the main contributors to Beijing’s pollution. China produces around 300 million tonnes of waste per year, and the waste is disposed off in landfills, which adds to the pollution problem. However, one good thing that can be seen in Beijing in the recent past is the use of contraceptives and healthy reproductive practices, which has controlled its growing population.

10. Osaka 

Population: 19,222,665

Osaka in Japan has such a large population that housing for people is one of the major problems. There are a number of high-rise buildings to accommodate the growing population, and combined with this is pollution, which is leading to many health hazards to its citizens. The Japanese government has been encouraging its citizens to move to other parts of Japan with lesser population. The government is hoping this will decrease population density, and improve the output and quality of work from within industries.

11. Karachi 

Population: 15,741,406

The financial city of Pakistan, Karachi has a population density of 24,000 people per square kilometre. According to the World Health Organization (WHO), Karachi’s air quality is twice as polluted as that of Beijing. Hence, the government, among its many initiatives, is planning to introduce a fleet of 200 eco-friendly buses to reduce carbon emissions in the city.

12. Chongqing 

Population: 15,354,067

This Chinese city has a population density of 350 people per square kilometre. Chongqing is home to major industries, and its average annual GDP growth rate is 9.5 percent, higher than the national average. Like most cities in China, the working-age population is shrinking, leading to rise in elderly population. Hence, the country abolished the one-child policy in 2015, and the government is considering to give incentives to encourage having a second child, according to Bloomberg.


13. Buenos Aires 

Population: 15,057,273

(Image: Shutterstock)

The capital city of Argentina, Buenos Aires has a population density of 13,680 people per square kilometre. According to the World Bank, ‘at the heart of the city’s urban challenges is the housing sector’. Responding to the problem, the National Housing and Habitat Plan has spent $6.4 billion to support over one million housing interventions in three years from 2016-2019.

14. Istanbul

Population: 14,967,667

With a population density of 2,523 people per square kilometre, the residents of Istanbul seem to unanimously agree that traffic congestion and transportation is a major problem in the city. But it has relieved itself over the years, thanks to Istanbul Metropolitan Municipality’s investment in transportation with a vision of smart urbanisation. 


15. Kolkata 

Population: 14,755,186

(Image: Shutterstock)

The capital city of West Bengal, Kolkata has one of the oldest operating ports in the country. Its population density is high, with 24,000 people per square kilometre. The city has a sex ratio of 899 females to 1,000 males. The State pollution control board stated that the pollution is seven times more than the limit set by the WHO.

16. Lagos

Population: 13,903,620

A port city in Nigeria, the density of population in Lagos is 6,871 people per square kilometre. The city is facing problems such as overpopulation, traffic, and poor sanitation. The state governor of Lagos, Babajide Sanwo-Olu, signed two executive orders in May this year to improve these conditions. He also declared a state of emergency.

17. Manila

Population: 13,698,889

Manila is the capital city of Philippines, and the world’s most densely populated city with 42,857 people per square kilometre. The city is also seeing a rising number of informal settlers. While the government has offered them subsidies to move to new homes in 2013, the dwellers still have a hard time making a living after relocation.


(Image: Shutterstock)

18. Tianjin

Population: 13,396,402

The city of Tianjin is one of the five national central cities of China. The density of population of the city is 1,300 per square kilometre. The city also witnessed one of the worst man-made disasters in 2015 when a warehouse that stored hazardous chemicals exploded and more than 170 people died. The government continues to focus on ‘human-centred urbanisation’, and aims to achieve 60 percent urbanisation rate by 2020.


19. Rio De Janeiro 

Population: 13,374,275

Rio De Janeiro is named as a ‘World Heritage Site’ by UNESCO. The city is home to major landmarks including the Christ the Redeemer which was erected between 1922 to 1931.  Population density of Rio is 5377 people per square kilometre. Most of the population is of Portuguese descent. Minority ethnic groups from Asia and Africa also inhabit the city. This year, the population increased by 0.61 percent.  

20. Guangzhou

Population: 12,967,862

Located in the northwest of Hong Kong. The city is part of the Pearl Economic Zone and has a population density of 2000 people per square kilometre. According to Guangzhou Urbanisation, people spend an average time of 36 minutes not moving in the city’s traffic. For this, in 2010, officials introduced a bus rapid transit in the city that could transport almost a million passengers. Last year, the government also introduced Management of Non-Guangzhou Registered Vehicles, which bans vehicles from outside Guangzhou after operating for four days.

(Edited by Megha Reddy)


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