Shenzhen has been rated the fifth most crowded city in the world, following Mumbai, Calcutta, Karachi and Lagos. It was also ranked first in population density in China by Forbes magazine.

The population density of Shenzhen was 17,150 people per square kilometer, followed by Shanghai at 13,400 people per square kilometer and Beijing at 11,500 people per square kilometer. The other two Chinese cities to have ranked among the 20 most crowded cities in the world were Taipei and Tianjin.

Mumbai had the world¡¯s greatest population density with 29,650 people per square kilometer.

Forbes said the quality of life in crowded cities was usually compromised because fast growth meant existing infrastructure was unable to meet the demands of residents. The happiness index of residents was therefore not very high in these cities, the magazine said.

There are now more than 14 million people living in Shenzhen. Of these, only some 2 million people have hukou, or permanent residence permit. The imbalance between hukou holders and non-hukou holders has caused serious problems for public security, education, health and other areas, the Guangzhou Daily said Saturday.

Besides population pressure, the city also faces problems such as increasing demand for land and serious traffic congestion during rush hour.