What is the greatness of Pushkar bath?

జనన ప్రభ్రుతి స్త్రియా వా పురుషేణ వా|
పుష్కరే స్నాతమాత్రస్య సర్వమేవ ప్రణశ్యతి||

Janna prabruthi yatpapam striyava purushena va|
Pushkare snanamatrasya sarvameva pranasyathi||

Meaning:

Whether it is female or male if they are going to do pushkar bath, they will be free from all their sins done from their birth.

That is why it is said that its just humans, even mukkoti gods also come to earth and have a bath.

Why do we say the word "Punyaniki pothe Papam yeduraindi"

In the story of great Mahabharata, Paila asks his shisya (student) Udanka to go to Poushya maharaja (king) and bring karnabharana as his guru dhakshina (offering). Upon his master's word, he goes to the king and conveys his master’s wish. King agrees to his wish and asks to have lunch as the guest is Brahmin. King orders to make delicious lunch, while having his lunch Udanka gets hair follicle in his rice.

Udanka gets angry with the type of food he was offered and curses the king to become blind. Simultaneously king also gets angry on the Brahmin and says the word “Punyaniki pothe Papam yeduraindi”i.e: as he not only granted his wish but also offered to have delicious food but indeed I was cursed. In return even King punished him.

At last both the king and Brahmin had to suffer. That is why our elders say that even though if you are willing to do a good thing, think before you do.