Above all this if the people additionally takes 108 rounds of the peeple tree during the fast and worships Lord Vishnu then more sins are washed away. Mainly the fast is observed by the women. On this day holy dips are taken in Haridwar, this can be observed from sunrise to sunset on this day.
The story behind the fast is that a moneylender had seven sons and one daughter. His all the sons got married but his daughter remained unmarried. In the house of moneylender a monk used to come and ask for alms and in return he used to give blessings to the daughter-in-law for happy and prosperous life but never gave any blessings regarding his daughter. Observing this the moneylender's wife got upset and called a pandit and told him to tell about her daughter's future and Kundali. Pandit disgracefully told that she will get widowed soon she is married. Mother got very upset and asked the Pandit for solution of this huge difficulty he asked that her daughter should go to island named Singhal, there a washer women lives the daughter has to ask Sindoor from that women and wear it on the forehead forever. Adding to that he also told her to observe fast on every Monday. Hearing this the moneylender's daughter and his youngest brother went along with her to the sea shore there they somehow found the washerwomen and then secretly the girl served the women, she got pleased by her humble behaviour owing to which she applied Sindoor on her forehead. Then the girl went to a peeple tree and then took 108 rounds and worshiped Lord Vishnu and that day was actually Somvati Amavasaya and still now it is celebrated.
This festival marks a significant ritual for married and unmarried women. They keep fast on every Monday and in return ask pray for their auspiciousness and happiness. Lord Shiv is worshiped every Monday. Women feed the Shiv Linga with milk and Gangajal. It is also done in order to get a smart, well build and loving Husband for the unmarried women, for married they pray for long life of their husband.