Complex sentence: Residents are mostly employed by the port (one of the largest ports of Europe) and maritime industry, yet lately residents of Odessa began relocating to lower-cost but higher-income Illichivsk.
Split into simpler sentences: Residents are mostly employed by the port (one of the largest ports of Europe) and the maritime industry. Residents of Odessa have recently begun relocating to lower-cost but higher-income Illichivsk.