When Savitri heard this she was outraged. She cursed her husband and declared that only at Pushkar would he be worshipped. However after the holy sacrifice Pushkar lake became so sacred that by merely bathing in its waters a mortal could go straight to heaven. Soon heaven became impossibly overpopulated…
And Brahma's fellow gods implored him to curtail his generosity. He agreed to limit the period of salvation to five days -- from the 11th day of Kartik, a month of the Hindu calendar to the 15th day or the full moon of Kartik. Thus the sanctity of a dip in Pushkar lake during these five days.