Guru Nanak Jayanti is observed in many Indian states on the day of the full moon in the month of Katak, which falls in October-November. This public holiday celebrates the birth of Guru Nanak, the founder of Sikhism, who was born on April 15, 1469. Guru Nanak shaped the core beliefs of Sikhism, emphasizing kindness, peace, and a rejection of revenge. The celebration of Guru Nanak Jayanti is marked by singing hymns and festive processions, with morning prayers often beginning as early as 1 am in some communities. This holiday is one of the most significant in Sikhism, reflecting the organized religious community that Guru Nanak established in Punjab.