Chhath puja is performed on Kartik Shukala Shashti, which is the sixth day of the month of Kartik in the Hindu Calendar, exactly 6 days after Deepawali. This falls typically in the month of October or November in the Gregorian Calendar.
Chhath is an ancient Hindu festival dedicated to Surya. The Chhath Puja is performed in order to thank Surya for sustaining life on earth and to request the granting of certain wishes.
The Sun, considered the god of energy and of the life-force, is worshiped during the Chhath fesival to promote well-being, prosperity and progress. In Hindu mythology, Sun worship is believed to help cure a variety of diseases, including leprosy, and helps ensure the longevity and prosperity of family members, friends, and elders.