The cities were flooded by new arrivals from European countries and African Americans.
Step-by-step explanation:
The whites were seeking opportunities to work in the industries with the coming up of urbanisation and industrialisation new opportunities were arising.
On the other hand the African Americans freed themselves from the farms and owners who didn't provide them with facilities. They came in search of some benefits and jobs just like other immigrants.
Though they were very easily targeted with the racial discrimination haltered. But they came in hopes to find better living conditions.