The Skanda Purana states that when Raja Indradyumna installed the wooden Deities, he arranged this Snana Yatra (bathing ceremony). The day is considered to be the birthday of Lord Jagannatha. Held on the full-moon day of the month of Jyeshtha, this festival is also simultaneously held in all other important temples at Puri. It attracts thousands of visitors and pilgrims from all over.
On the previous day of Snana Yatra, the Deities of Jagannatha, Balabhadra and Subhadra along with the Sudarshana are ceremonially brought out from the sanctum in a procession to the snana-vedi (bathing pandal). This special pandal in the temple precincts of Puri is called Snana Mandap. It is at such a height that visitors standing outside the temple gate also get to see the Deities.
On the fourteenth day (Chaturdashi – the day before the bathing – Purnima) when the Deities are taken out in a procession, it is called Pahandi. As the Pahandi of the Deities takes place to the accompaniment of music and beating of drums, thousands of devotees jostle and crave for a look at the Deities.
In Puri the bathing procedure is as follows: After Mangala Arati, the Suaras and Mahasuaras go in a ceremonial procession to fetch water from Suna Kua (golden well) in one hundred and thirty vessels of copper and gold. All of them cover their mouths with a piece of cloth so as not to contaminate it even with their breath. The Palla pandas (a class of Brahmin priests) then purify the water with Haridra (turmeric), Java (whole rice), Benachera, Chandan, Aguru, flowers, perfumes and medicinal herbs.
The bathing festival takes place during the morning hours of the purnima tithi. The filled vessels are carried from Bhoga Mandap to the snana vedi by the Suaras in a long single-line procession. This ritual is called 'Jaladhibasa' (Jala – water, abhishek – bath).
Due to the amount of bathing liquids that are offered to cool the Lord's transcendental body during this hot season, His painted form gets discolored as the Deity’s faces are done with natural earthly mineral paints. To bridge the episode of His bathing and the period that He comes out to bless everyone for Ratha yatra He organized some special pastimes by which the devotees can serve Him and remember His wonderful forms.
So the Lord arranged for the Hati Vesha festival, where Lord Jagannatha and Lord Balarama then put on the elephant dress, Hati Vesha, and Lady Subhadra wears a lotus flower vesha. The original story is told in several different ways, some call Hati snan (elephant bath) some call Ganesh abhishek as they identify the following story as being the original cause of the Lord to wear this elephant vesh for His devotee: It is said that a scholar who was a staunch devotee of Lord Ganesh visited Puri during Snana Yatra. He was amply rewarded by the king of Orissa for his scholarship. The king asked the scholar to accompany him to see Lord Jagannatha, which he refused under the pretext that he wouldn't worship any "God" other than his Ishthadevata Ganesh. Somehow he was persuaded and brought before the Snana vedi. To the utter surprise of all, Lord Jagannatha appeared with an elephantine form that resembled Ganesh. Since then during Snana Yatra when the sacred bath is performed, the Deities are dressed like elephants – resembling Ganesh.
During the sacred bath, the colours painted on the images generally fade. Seeing the wooden Deities discoloured, devotees may not have the appropriate devotional attitude. For this reason, the images are immediately dressed in the Hati vesha (besa) in which they remain mostly covered.
After the Snana Yatra, the Deities are kept away from public view for fifteen days and during all these days the daily rites of the temple remain suspended. During these fifteen days, the Daitas (descendants of Vishwavasu, the Savara) repaint and restore the Deities and Jagannatha’s fine decorations. On the 16th day, the Deities in their new forms after renovation become ready for darshan. The festival of the first appearance of Lord Jagannath to His devotees is called Netrotsava (festival for the eyes) or Nava Yauvanotsava (festival of the ever new youth). According to priests of the Jagannatha temple, the devotee washes away all his sins if he gets a vision of the Lord on this day.
The Shilpa Shastras and Agamas testify that the Deities become suitable for worship only after the performance of the rite of 'Chakshyu Unmilana' (opening of the eyes). During 'Anabasara', the Daitas offer the Deities only fruits and water mixed with cheese and dasa mula medicines to cure His fever. In a devotional mood, the devotees accept that due to all the bathing, the Lord becomes transcendentally poor, and therefore needs to take rest. Like human beings, They are considered to have fallen ill and are treated by the Raj Vaidya or the King's physician with specific medicines.
The temple-festivals which are held in a bigger and elaborate scale in the important shrines of Puri and Bhubaneswar are also held simultaneously in all other smaller shrines of the respective Deities, though in modest scales. Likewise the Snana Yatra is held in many other temples of Odisha, and now all over the world.