Complex sentence: An official launch event was about to held on 12 December 2015, coinciding with Rajinikanth's birthday, but the team chose to avoid publicity as a result of the 2015 South Indian floods.
Split into simpler sentences: An official launch event was to be held on 12 December 2015, coinciding with Rajinikanth's birthday. However, the team chose to avoid publicity as a result of the 2015 South Indian floods.