Vat Pournima is the women's festival of India,especially celebrated in Maharashtra and Karnataka states.This falls in the month of Jeshtha (May-June),on the full moon day.
As per the rule,the Vat Puja fasting is observed for 3 days.But nowdays,because of their busy schedule,the women observe it only for one or two days.Married women take a sacred bath and wear new clothes and bangles,also apply sindoor (vermilion) on the fore-head and observe fasting.
Women gather at the banyan tree in their locality.Holy water from the river Ganges is sprikled on the tree and threads are tied around the tree.Haldi,kumkumis applied to the tree.Then fruits and flowers are offered to the tree.Lamps are lit and the Arti is shown.
Women read and recite Savatri Katha' in the evening and do ritual puja.Later, they eat the roots of Vat vriksha along with water. At the end of the day, women touch the feet of husbands and take blessings of elderly people
As the story says- It was predicted that Satyavan had a short life and will not live long more that one year..
Satyavan was lyeing on the lap of his wife Savitri,under a banyan tree as his end time came near.A day arised when the messenger(Yamdoot) of Yama,the God of death came to take Satyavan's life.
Savitri who loved her husband like her own soul, refused to give her beloved husband in the possession of the Yamdoot.The Yamdoot tried tried his level best to take Satyavan away, but in vain. Finally,Lord Yama himself had to appear in front of Savitri and request her to give her husband's possession.
Savitri was still very adamant and told Yama that in no case she would leave her husband.The Lord Yama was convinced with the wife's love and affinity for her husband and finally offered her a boon.
She asked for the well being of her in-laws/.Lord Yama soon granted it to her.She still followed him as he took Satyavan's body away.Then he offered her another boon,when she asked for the well being of her parents. This boon, too , was granted by Lord Yama.
But Savitri still continued to follow him till the Yama's abode.Here Lord Yama offered her a final boon,when she asked for a son and Lord Yama granted it.She immediately questioned Yama, how it was possible to get a son without the husband.
Yama came in to a trap and he had to spare her husband and hand over back to her.So,married women pray to the banyan tree,in the honour of the Savitri's love for her husband and ask for the well being of their in-laws,parents and longetivity and prosperity of their husbands and children.They observe a fast from the night till the next morning.