@Hans: thank you for your answer, but it seems difficult to reduce population size or stop its growth, so the only choice is to adjust the cities for larger amount of population with the same space. Some town planners advocate a vertical city as the solution to solve increasing density of population in the large metropolis. What do you think.? Thanks
I would be an advocate for the more densely populated city as well. I think life is actually better in these kinds of places if there are distributed services (grocery stores, banks, schools, etc.) that are available by walking or public transport. The big spread out metropolis is the worst way to go. Traffic is awful in Mexico City, Los Angeles, Sao Paulo, and many Asian cities. Many of the cities do not have tall buildings, and take up an enormous space in the landscape. It is not humane to live in these places. The pollution from cars is a hazard, and the frustration of driving on crowded roads is equally deleterious. There is a great book about the value of dense cities, called The Geography of Nowhere by James Kunstler. It is a great read on this topic, focusing on cities in the USA that just went the wrong way.