This year Navratri is celebrated/ observed on Thursday September 21st, 2017. Navratri is a 9 day festival dedicated to the Hindu deity Durga which starts on the first day of the Lunar month of Ashwin. In Sanskrit Navratri broken up mean nine nights.
Hindus celebrate this festival over the course of nine days with each day celebrating a different form of the goddess of power Durga. Over the course of the nine days there are singing, plays, rituals, and dances all in celebration of the festival.
This day is born out of legend and include Maa Durga and Lord Ram. Mahishasura was a buffalo faced demon who Goddess Durga defeated over the course of nine days of fighting and finally killing him on the tenth day. The main theme of the festival is the triumph of good over evil.