Complex sentence: The city's industry grew rapidly, especially after some factories were evacuated there from the west of the Soviet Union during the World War II. Later the city was an important centre of arms development and production and still remains an industrial centre.
Split into simpler sentences: The city's industry grew rapidly, especially after some factories were evacuated there from the west of the Soviet Union in the WWII times. During Soviet times the city was an important centre of arms development and production and still remains an industrial centre.