When Lord Ram and Sita Mata returned to Ayodhya after 14 years of exile, they decided to perform Rajsurya Yagya on the orders of sages to absolve themselves of the sin of killing Ravana. He invited Mugdal Rishi for the puja. Mugdal Rishi purified Mother Sita by sprinkling Ganga water on her and ordered to worship the Sun God on the sixth day of Shukla Paksha of Kartik month. Due to this, Sita stayed in the ashram of Mugdal Rishi and worshiped the Sun God for six days. On Saptami, at the time of sunrise, the rituals were again performed and blessings were obtained from the Sun God.

It is believed that worshiping Sun God on the day of Chhath increases the happiness, prosperity and good fortune of the fasting people. This fast was started during the Mahabharata period. It is believed that the children of women who fast on this day remain in good health and their children get a long life. That is why mothers observe this fast for their children.

The scientific reason behind celebrating this festival is that the Sun is worshiped in this festival. A person whose Sun is strong in his horoscope can take decisions well. By standing in water and worshiping the sun, the effect of sunlight is doubled. A person’s decision making ability is good. If we talk about giving water to the sun, the science of colors is hidden behind it. Due to imbalance of colors in the human body, there is a risk of falling victim to many diseases. While offering water to the Sun God in the morning, these colors get balanced by the light falling on the body. Due to which the immunity power increases. Skin diseases are reduced. Vitamin D obtained from sunlight is fulfilled in the body.
If seen from a scientific point of view, a special astronomical change takes place on the day of Shashthi. Then the ultraviolet rays of the Sun gather abnormally and to avoid their ill effects, Chhath fast is observed by standing in water during the Sun’s Usha and Pratyusha.

Chhath is not just a religious ritual, there is science also hidden in it. Those observing fast are physically and mentally prepared for it. The things used during Chhath Puja are as per autumn season. Fertility increases in the month of Kartik and Vitamin D is very important for pregnant women. Therefore the tradition of Surya Puja has been created.

Draupadi had kept a fast on Chhath for the good health and better life of her husband. When Pandavas lost the entire kingdom in gambling, Draupadi observed Chhath fast. With this fast their wish was fulfilled and the Pandavas got everything back. During this fast, Draupadi worshiped Surya and worshiped Chhath Maiya. It is also believed since ancient times that during the Mahabharata period, Surya’s son Karna had also worshiped Chhath. Karna was a great devotee of Lord Surya. He used to stand in waist-deep water for hours every day and offer prayers to the Sun. It was only by the grace of Surya that he became a great warrior. Even today the same tradition of donating Arghya during Chhath is prevalent.

According to mythological texts, Shashthi Maiyya is the mental daughter of Lord Brahma and sister of Sun God. Shashthi Maiya is worshiped in this fast, hence it is also known as Chhath fast. According to the Puranas, to create the universe, Lord Brahma divided himself into two parts, in which the form of man appeared in the right part and the form of nature appeared in the left part. A part of Goddess Nature, the presiding deity of creation, is also known as Devasena. Due to being the sixth part of nature, a popular name of this Mother Goddess is Shashthi, who is known as Chhathi Maiyya.