Dev Deepavali is a celebration of light, pleasure and spiritual festival which signifies enlightenment, existence of life, sign of immortality and victory of good over evil. It is celebrated on the fifteenth day of Diwali, on the occasion of Kartik Poornima when the Ghats of Varanasi come alive with thousands of Diyas. Usually it falls on the on the full moon day in the month of Kartik (also known as Kartik Purnima (November-December). The festival, also known as Kartik Purnima, Tripuri Purnima or Tripurari Purnima, coincides with the Jain light festival and Guru Nanak Jayanti.

Dev Deepavali is held as tribute to river Ganga by the people of Varanasi and Ganga-Aarti is an important event held on this day. On the festive eve, the entire riverbank of the city are decorated with thousands of brightly-lit earthen lamps ('Diya') as a symbolic welcome to the Gods as they descend on Earth. A four day long Ganga Mahotsav is organised by the Uttar Pradesh Tourism Department as a part of Dev Deepavali with several cultural programmes.