Nirjala Ekadasi is the most austere and most sacred of all twenty-four Ekadashi fasts observed throughout the year. Popularly known as Pandava Bhima Ekadashi or Jyeshtha Shukla Ekadashi, the holy festival falls on the 11th lunar day (Ekadashi) of the waxing fortnight of the Hindu month of Jestha (June), as per traditional Hindu calendar. Derived from the name Nir-jala (water-less), the devotees observe absolute fast without partaking even water on this pious day.
According to the Vedas (Hindu religious books), the movement of the moon and day of Ekadashi has a direct correlation with the human mind as they believe mind attains maximum efficiency on the very day, giving the brain a better capacity to concentrate. Though all Ekadashis are believed to owe its favorable influence on the human mind, Nirjala Ekasahi holds the especial significance, granting the virtue gained by the observance of all 24 Ekadshis in the year. Observing religious fast on the very day is considered equal to going on pilgrimage and it is also believed that the devotees, who observe this fast, after death, gains salvation (moksha) and is received by messengers from Vaiskuntha (adobe of Vishnu) not by Yama (the god of death).
Moreover, Nirjala Ekadashi is one of the strictest fasts in Hindu religion; it is observed for 24 hours which begins from sunrise and ends next morning by drinking water, tulsi leaves, fruits and sweets. One day before the fast, the devotees perform Sandhyavandanam (evening prayer), taking only one meal without rice. On the day of Ekadashi, they observe absolute fast without consuming any food and partaking even a single drop of water. Like in any other Ekadashis, Lord Vishnu is worshiped in the form of Tulsi in Nirjala Ekadashi. It is believed that the Lord transformed himself into Tulsi to redeem humans from sin. An image of Vishnu or a Saligrama (an iconic fossil stone in the form of Vishnu) is bathed with Panchamrita (a mixture of five foods: milk, curd, ghee, honey and sugar). It is then washed with water and dressed in royal finery. Devotees visit Vishnu temples, mediate on the image of Lord Vishnu, and offer puja to ensure happiness, prosperity and forgiveness of transgressions and sins to him. They remain awake the whole night, singing the praises of Vishnu and also donate clothes, milk, food grains etc to Brahmins to acquire Punya.
Looking back to the legend of the festival, Bhima-the second and the strongest of the five Pandava brothers, was a great lover of food. He wanted to observe fast in all Ekadashis but could not control his hunger. For the solution, he approached the sage Vyasa- author of the Mahabharata and grandfather of the Pandavas. The sage explained him the benefits and merits of Ekadashi fasting and advised him to observe Nirjala Ekadashi, when for one day in the year, he should observe an absolute fast. Bhima attained the virtue of all 24 Ekadashis, by observing Nirjala Ekadashi.
Hence, Nirjala Ekadashi is considered as the most auspicious, purifying, sin devouring and virtue granting Ekadashi. It is the toughest among all Ekadashi fastings but if observed religiously, the devotees are believed to be blessed by Lord Vishnu, granting all the happiness, prosperity and a blissful life.