In mexico the most devastating effect of the columbian exchange was

Small pox. Killed 50% or more of Amerindians population in Mexico and Central America

Ifound this on google “the existence of agglomeration economies is central to the explanation of how cities increase in size and population, which places the phenomenon on a larger scale. the concentration of economic activity in cities is one reason for their development and growth.” i hope this you for what your looking for.