The factor of 'population clusters in cities' has not contributed to a 'dramatic increase in the world's population' in recent centuries.
Explanation:
The population clusters in cities apparently and practically do not have anything to do with the dramatic increase in the world's population.
The population clusters formed in the cities are just another result of rapid urbanization.
These clusters stand responsible for the exploitation of resources and making it difficult for the lower classes of the population to lead an easy life.