We are in the month of Kartik. The festival, which lasts three days, involves the preparation of special foods, not contaminated and offering prasad at major temples places near water. The morning offering to the sun coincides with the end of a fasting purification. The demands made on Surya are those of wealth, health and purification, particularly of the skin.
Many go at dawn at the lakes, ponds. These rituals have ancient origins. The first to pray to the sun to get the health of loved ones seems to have been Draupadi in the Mahabharata. Surya who can illuminate the way! The Chhath festival is the only one dedicated to Surya, the sun god.
The rituals of the festival are very strict and involve a period of four days during the month of Kartika, the month of the Hindu calendar which corresponds to our October or November.
The festival is particularly strong in the north east of India but is celebrated by the Hindu faithful a little everywhere.