Treta Yugadi is believed to be the day when Treta Yuga started. It is the second among the four Yugas in Hindu Religion – Satya (or Krita Yuga), Treta, Dwapara and Kali Yuga, which is the present era. It is believed that Treta Yuga began on the Akshaya Tritiya day. For some communities it is the day after Diwali.
Yuga is defined as epoch or era and there are four yugas as per Hindu tradition in a cycle; after which there is a complete dissolution and the cycle is again repeated.
Treta is the second yuga and Brahmanda Purana suggests it lasted for 1296000 human years.
Treta Yugadi celebrates the day when the Treta Yuga began.