Source: Mohammad Shadab Alam / iStock via Getty Images
20. Aligarh, India
> Population density: 54,368 people per square mile
> Population: 2.1 million
> Built-up land area in city: 38 square miles
Source: burakkarademir / iStock Unreleased via Getty Images
19. Ahmadabad, India
> Population density: 55,518 people per square mile
> Population: 7.7 million
> Built-up land area in city: 139 square miles
Source: X_world / Getty Images
18. Patna, India
> Population density: 55,983 people per square mile
> Population: 3.2 million
> Built-up land area in city: 58 square miles
Source: Sanjog Mhatre / iStock via Getty Images
17. Mumbai, India
> Population density: 57,033 people per square mile
> Population: 22.2 million
> Built-up land area in city: 389 square miles
Source: By Faris knight - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=34986720 / Wikimedia Commons
16. Al-Mahallah, Egypt
> Population density: 57,857 people per square mile
> Population: 810,000
> Built-up land area in city: 14 square miles
