Karachi is Huge:
The report says that Karachi is the world's 7th largest metropolis with an estimated population of nearly 21 million inhabitants packed in an area of 310 square miles, making it the 10th densest large city in the world. Demographia authors acknowledge that their estimate of Karachi's "population is lower than other estimates (such as the United Nations), which include metropolitan area population not within the continuously developed urban area".
Massive Influx of Migrants:
In addition to the normal migration patterns witnessed in the past, Karachi has also seen major influx of waves of refugees escaping conflict zones like FATA and Swat and many people dis…