There are several stories associated with the festival of Karwa Chauth.
Queen Veervati’s Story
Long time ago there lived a beautiful queen Veervati, who was the only sister of her seven loving brothers. She observed her first Karwa Chauth at her parent’s home. She took a stern fast after sunrise on the very particular day, but by evening she became desperate for moonrise as she suffered from severe hunger and thirst. Her brothers couldn’t bear to see her in such a suffering and hence they created a mirror in a ‘pipal’ tree, which made it appear as though the moon had risen. Veervati mistook it and she broke her fast. The moment she took her first morsel for the day, word arrived that her husband is dead. Being heartbroken she cried for the whole night. As she was a Pati-vrata woman, her shakti compelled a Goddess to appear & ask the reason behind her grief. When Veervati explained her pain, the Goddess revealed the tricks of her brothers and she also instructed her to repeat the Karwa Chauth fast with utter devotion. When she completed her fast with full dedication, Yama the God of Death was forced to restore her husband’s life.
The belief associated with this fast goes back to the pre-Mahabharata period. Draupadi, the wife of Pandavas, too is believed to have observed this fast. Once Arjuna went to the Nilgiris for reparation & the rest of the Pandavas experienced many problems during his absence. Draupadi, out of extreme anxiety called Lord Krishna & asked for his help. Lord Krishna then reminded her that on an earlier event, when Goddess Parvati had required Lord Shiva’s direction under similar circumstances, she’d been guided to observe the fast of Karwa Chauth. In this legend, Shiva told Parvati the story of Veervati and described the importance of Karwa Chauth fast. Draupadi followed the guidance & observed the fast with all customs and rituals. Consequently, Pandavas overcome their problems.
Satyavan & Savitri Story:
When Yama- the God of Death, came to seize the soul of Satyavan, Savitri begged for his life. When Yama refused, she denied eating and drinking & went after Yama who carried away her departed husband. Yama told that she could ask for any other bliss or boon except for her husband’s life. Savitri asked to be blessed with children. Yama agreed on this boon and granted the same. Being a Pati-vrata wife, SAvitri would never allow any other man to be the father of her kids. Yama was left with no other way but to her husband’s life. And hence, her husband came to life and this festival is observed with same aim to keep the husband away from any problem.
There lived a woman named Karwa who was a Pati-vrata woman means she was deeply devoted to her husband. Her extreme dedication and love towards him endowed her with spiritual power (shakti). While bathing in a river, a crocodile caught her husband. Karwa tied the crocodile with a cotton-yarn & asked Yama to send that crocodile to hell. Yama however refused her request, and then she threatened to curse Yama & destroy him with her shakti. Yama, terrified of being cursed by Pati-vrata wife, sent the crocodile to hell & blessed her husband with long life. Karwa & her husband relished many years of wedded bliss. To mark this day, Karwa Chauth is rejoiced with great faith & belief.