Ah well, it’s a significant problem in many parts of America. Pretty much every metropolitan area has ethnic segregation to some extent among geological lines. This is due to a variety of factors- white flight, a long history of oppression and a fairly recent desegregation movement, towns where black people weren’t allowed to stay the night, generational discrepancies exaggerating existing effects, etc.

It’s fairly normal for there to be a wide variety of reasons why specific areas are predominantly one or another ethnicity.