Nirjala Ekadashi falls on the 11th lunar day (Ekadashi) of the waxing fortnight of the Hindu month of Jyestha (May/June), therefore it is also called "Jyeshtha Shukla Ekadashi" or "Bhimsani Ekadashi" (Bhim sen, the seond Pandav Brother, had observed this difficult fast). The ekadashi derives its name from the water-less (Nir-jala) fast observed on this day. It is considered as the most austere and hence, most sacred of ekadashis. If observed religiously, it is said the most rewarding and granting the virtue gained by the observance of all 24 Ekadshis in the year. People observe strict fast and offer pooja to Lord Vishnu to ensure happiness, prosperity and forgiveness of transgressions and sins.