The toughest and most important of all 24 Ekadashis in a year, Nirjala Ekadashi is on June 5 (Monday). The reason why it is regarded as the hardest of all the Ekadashis is that one cannot be allowed to have water and any type of food in this fast.
Talking about its meaning, Nirjala means without water and Nirajala Ekadashi means fasting without water & food.
People who don’t observe all Eakadashi fasting in a year, observe this fast as it is said that it alone brings all benefits of 24 fasts. Nirjala Ekadashi also known as Pandava Ekadashi and Bhimseni or Bhima Ekadashi.
In Nirjala Ekadashi, people wake up early in the morning and take bath ahead of worshipping Lord Vishnu. And in order to mental silence, people chant ‘Om Namo Bhagavate Vasudevaya’ mantra.
Later, in the evening people again worship Lord Visnu and have dinner at night. Next day (June 6), people call priests and offer them food.