Complex sentence: The Koreatown area of Manhattan is primarily a Korean business district, but in recent years, the district has seen an increase in Korean and European traffic as well, and the resident Korean population in the area has grown concomitantly.
Split into simpler sentences: The Koreatown area of Manhattan is primarily a Korean business district. However, in recent years, the district has seen an increase in Korean and European traffic as well, and the resident Korean population in the area has grown concomitantly.