Why do poor people generally bypass the small cities and directly come to the megacities for their livelihood?

Due to low opportunities in smaller and medium cities. Due to high opportunities in smaller and medium cities. Due to low pollution in smaller and medium cities. Due to high pollution in smaller and medium cities.

Due to low opportunities in smaller and medium cities.

Due to low opportunities in smaller and medium cities, poor people generally bypass these small cities and directly come to the mega cities for their livelihood.