With a population density of 44,500 people per square kilometre, Dhaka, the capital of Bangladesh, is the most crowded city on the planet, followed by India's financial capital Mumbai, home to 31,700 people per square kilometre at the second place.
Kota in Rajasthan with 12,100 people per square kilometre was ranked seventh.
Others in the list include Medellin in Columbia ranked third with 19,700 people per square kilometre, Manila, Philippines (4th, 14,800), Casablanca, Morocco (5th, 14,200), Lagos, Nigeria (6th, 13,300), Singapore (8th, 10,200) and Jakarta, Indonesia (9th, 9,600).
"There are various reasons why vast numbers of people decide to settle in urban areas, but in the majority of cases it boils down to the simple fact that cities are where the work is," WEF said.
Kibera, Africa's biggest slum, is just 5 km from Nairobi city centre and is infamous for its poverty and its metal shacks built millimetres away from railway lines, while Dharavi in Mumbai has a reported density of over 200,000 people per square kilometre, the report said.
"There are clearly pros and cons to being a city dweller, although people's overall quality of life will always depend on where they can afford to live," it added.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)