Overcrowding is a term given to places filled with people as a result of overcrowding and resulting from not taking into account the space of the place and the number of people heading to it , As is noticeable in some countries, including rich and developing ones, the population density increases significantly, and major cities are defined as urban areas with a population of more than 10 million people.

The population density varies from one place to another based on many factors, the most important of which is the availability of all ways of life, which are among its priorities (food, water, and work) in addition to the difference in needs with the tremendous technological progress that changes and develops on a daily basis, the land is constantly developing and changing from day to day. As its population continues to grow, cities become more crowded and resources become scarcer. Researchers estimate that the world's population in AD 1000 was about 275 to 300 million, today, the number is estimated at 7.8 billion.

Here is now a small overview of some cities: The city of Tokyo increased only 559,000 people between 2010 and 2020, and it is the capital of Japan, the country that has dazzled the entire world for its scientific progress. The population of Tokyo has reached nearly thirty-eight million people, which made it ranked It is the first in the world in terms of population density, but this number does not represent a problem for it due to its economic strength.

But on the other hand, Indian and Chinese cities continue to grow rapidly in the coming years and the population of Delhi is expected to exceed the population of Tokyo by 2028, the city of Delhi has increased more than 8 million people in the same time frame and the city of Shanghai has also increased by more than 7 million person. Meanwhile, São Paulo has grown by more than 2 million, and Mexico City has gained just over 1.6 million people.

China is home to four of the most populous cities in the world, with Beijing the capital coming in second. In addition, the population of the giant city is expected to increase by 5 million people by 2035, and Shanghai is also one of the largest Chinese cities in terms of area and population, with a population of nearly twenty-three million people, and it has great economic value Because of its global industrial status.

(Mexico City) is one of the largest Mexican cities, with a population of approximately twenty-one million, while the number in 1950 AD did not exceed three million. The federal capital of Mexico is also considered one of the cities that belong to the Federation and one of the most important areas It plays a major role in many matters relating to the state and its affairs.

(Istanbul) drivers spend about an hour in congestion, to reach a destination that is a quarter of an hour away in the normal case, and to address this problem, a tunnel was built that crosses under the Bosphorus Strait, to extend the metro network in the city, (Cairo city) Cairo is often seen on It is a city closely connected to ancient Egyptian history, particularly due to the location of the Giza pyramids, but it is also a densely populated cosmopolitan city, with a population of nearly 21 million.

(Mogadishu, Somalia) Population: 2.3 million Population density: 64,700 / sq mi To get around the city we seriously advise you not to do this because you need to rent a jeep and fully armed with security, (São Paulo, Brazil) Sao Paulo is the Brazilian city The most populous in the Southern Hemisphere, with a population of over 22 million. São Paulo is also a multicultural city with diverse industries.