Though today is the fourth day of Navratri, instead of the fourth form of Nav Durga, which is Goddess Kushmanda, Skandamata — the fifth avatar of Goddess Durga will be worshipped. This is because the Panchami Tithi is falling on October 10. Basically, this year, the fourth day of Shardiya Navratri will be dedicated to the fifth incarnation of Shakti — Maa Skandamata.