Complex sentence: The mid- 20th century saw a decline in the occupations of the people of Devipattinam, with the advent of the surface transport the Merchant Navies faded away and Devipattinam ceased to be a harbour and port.
Split into simpler sentences: The mid- 20th century saw a decline in the occupations of the people of Devipattinam. With the advent of the surface transport the Merchant Navies faded away and Devipattinam ceased to be a harbour and port.