It is an ancient Hindu festival dedicated to Surya, the chief solar deity and “Chhati Mai”, Goddess of Power.  This major festival is also celebrated in the northeast region of India, Madhya Pradesh, Uttar Pradesh, and parts of Chhattisgarh. Even in Tamil Nadu, the migrants from the north celebrate Chhath beside the sea beach. Hymns praying to the sun can be found in the Vedas, the oldest sacred texts of Hinduism.

People celebrate this festival with a great pomp and show. The devotees take a dip or shower (Ganga Snaan), preferably in the sacred Ganges before the actual worship and also bring some holy water (Ganga Jal) to prepare the offerings.
A fast is observed for the whole day and broken late in the evening after worshipping the deities at home. The PRASAD would constitute typically of rice porridge (kheer), puris (deep fried puffs of wheat flour) and bananas.  The Prasad is then shared among family, friends and relatives.
On the second day, the 24-hour fast begins. The day is spent in the preparation of offerings at home and in the evening, the devotees move to a riverbank (or a pond). There, offerings are made to the setting sun. At nightfall, the devotees return home where another colorful celebration takes place. Under a canopy of sugar cane sticks, clay elephants containing  earthen lamps, and containers full of the offerings are placed. There the fire God is worshipped. Devotees maintain a strict fast without even water. Just before sunrise, the devotees reach the riverbank again and offer prayers to the rising sun. Once the prayers are done, the devotees break their fast with the Prasad or the offerings. After that, the prasad is distributed among family, friends and relatives. The offerings characteristically consist of deep-fried and sweet rolls of stone ground wheat flour, grapefruit, whole coconuts, bananas, and grains of lentils. During the puja, these items are contained in small, semicircular pans woven out of bamboo strips.

• In the ancient epic Mahabharata, references to worshipping of the sun by Draupadi, wife of the Pandavas, are found. It was believed that worshipping of the sun would help cure a variety of diseases, including leprosy, and also ensure longevity and prosperity of the family members, friends, and elders. It is also believed that Chhath was started by the great Danveer (alms giver) Karna, sired by the Sun God, who became a great warrior and fought against the Pandavas in the Mahabharata war.
• Chhat Pooja or Surya Sashti vrat is observed by King Karna, the son of Surya, who was renowned warrior and well-known for his nature of charity. Since Karna became a popular King by observing Surya Puja, Hindus also worship Surya dev for courage, fame, health, wealth and prosperity.