Basanti Puja, also known as Chaitra Durga Puja, represents the Original Puja, and is observed during the Chaitra Navratri -a celebration of nine days where each of the nine days are dedicated to the nine different avatars of Goddess Durga. It is believed that Goddess Durga arrives from heaven to stay with her devotes during this time, and so it Is considered to be an auspicious time.
This puja is based on the belief that Durga Puja was originally held during Spring season, or Basant, to observe the Spring equinox. It was Lord Ram who changed worship period of Goddess Durga from Chaitra to Ashwin (October – November). He had invoked Goddess Durga in Ashwin month to get her blessings before starting his campaign against demon King Ravana in the Ramayana. The name Basanti puja is famous in eastern parts of India, especially in Bengal, Assam, Manipur, Tripura, Orissa, Arunachal Pradesh and Jharkhand. Mother Goddess is worshiped in North and Western parts of India during the same period for nine days starting from Chaitra Shukla Paksha Pratipada Pratipada (the first day after the new moon in the month of Chaitra).