Complex sentence: The refit was completed on 4 September, and the carrier was towed back to Mumbai on 23 October for her formal decommissioning ceremony, scheduled for the end of 2016 or in early 2017; her weapons systems and operational equipment will be removed by mid- 2017.
Split into simpler sentences: The refit was completed on 4 September, and the carrier was towed back to Mumbai on 23 October for her formal decommissioning ceremony. After "Viraat's" decommissioning, her weapons systems and operational equipment will be removed by mid- 2017.