Usually the high density is actually a problem for future growth. For one, there are concerns about the mass of people being exposed to various risks, primarily

Usually the high density is actually a problem for future growth. For one, there are concerns about the mass of people being exposed to various risks, primarily related to sanitation. Then the high density becomes a problem for further development, because any change involves dealing with more people and problems, making things more cumbersome and expensive. This is where a city like New Delhi "grows" by simply sprawling with slums. This in itself is not that attractive for quality people.