The God of light, life force and energy is worshipped in order to promote well-being, development and the prosperity of human beings. Devotees express their gratitude towards Lord Surya and perform important rituals over a for a span of four days. People who observe the fast during this festival are called Vrati.
In both Nepali and Hindi languages, the word Chhath means six. And hence, this festival is celebrated on the sixth day of the month of Karthika. Therefore, the festival is named Chhath.
There are several legends that explain in detail the origin of Chhath Puja. It is believed that in ancient times, Draupadi and the Pandavas of Hastinapur used to celebrate Chhath in order to solve their issues and gain their lost kingdom again. A few mantras from the Rig Veda texts are chanted by worshippers while offering prayers to the Sun.
According to another legend, Chhath Puja was first performed by Karna, who is considered to be an offspring of Lord Surya and Kunti. He ruled over the Anga Desh which is the modern-day Bhagalpur in Bihar, during the age of Mahabharata.
As per a legend, Chhath Puja is being performed from the Early Vedic Period. The legend has it that the sages of that era used to perform the puja by exposing themselves to direct sunlight to gain energy from the rays of the Sun and did not consume any eatables.