On AtlanticCities - Meet Dhaka, the World’s Densest Metro Area:
How dense is Dhaka? According to a July study by Demographia [PDF], its 15,414,000 inhabitants live within 134 square miles, giving the city a suffocating density of 115,000 inhabitants per square mile. Among the world’s top thirty metro areas, Mumbai is a distant second (80,100 psm), Karachi is third (66,800 psm), and fourth is Kinshasa, with 40,200 per square mile, or one-third the human density of Dhaka. Of all the world’s metro areas, only Hyderabad, Pakistan approaches the density of Dhaka, with 100,900 people per square mile, but the Pakistani city is home to only 2.8 million people.
Data is from Table 1 from the Demographia pdf, shown above.