Complex sentence: Most of the dead were from the states of Andhra Pradesh, Karnataka, Tamil Nadu and Kerala, who were going back home through the forest after Makara Jyothi darshan, thought to be a celestial phenomenon, on the hill shrine of the Hindu God Ayyappan.
Split into simpler sentences: Most of the dead were from the states of Andhra Pradesh, Karnataka, Tamil Nadu and Kerala. The victims were going back home through the forest after Makara Jyothi darshan, thought to be a celestial phenomenon on the hill shrine of the Hindu God Ayyappan.