Chhath (Hindi: छठ, also called Dala Chhath) is an ancient Hindu festival dedicated to the Hindu Sun God, Surya, also known as Surya Shashti. 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 Hinduism, 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.
The rituals of the festival are rigorous and are observed over a period of four days. They include holy bathing, fasting and abstaining from drinking water (Vratta), standing in water for long periods of time, and offering prashad (prayer offerings) and aragh to the setting and rising sun.
Although it is observed most elaborately in Bihar, Jharkhand and the Terai regions of Nepal in modern times, and is more prevalent in areas where migrants from those areas have a presence, it is celebrated in all regions and major urban centers in India.