India celebrates Dev Deepawali every year during the full moon of the Kartik month. Dev Deepawali festival occurs on Kartik Purnima and Diwali festival occurs on Kartik Amavasya. The Dev Deepawali occurs 15 days after Deepawali festival. During this day, Kashi or Varanasi is bustling with devotees, and the temple ghats are beautifully illuminated with lamps and diyas. On this day, there is also Ganga Pujan and Aarti. As part of the worship of Lord Shiva in Kashi, devotees take a dip in the sacred Ganga. The festival is celebrated by worshipping different deities. Several believe it commemorates the birthday of Lord Kartik, the son of Lord Shiva, others believe Lord Vishnu come swarg look from paatal lok, whereas others believe it celebrates the day in which Lord Vishnu assumed his first form.
Each year, thousands of devotees from across India and even abroad flock to the world-renowned festival of Dev Deepawali, also known as Kartik Poornima. Varanasi celebrates Dev Deepawali 15 days after Diwali on the full moon in the Hindu month of Kartika, which falls 15 days after Diwali. Tripurasura was killed by Lord Shiva on this day as he was in the form of Tripurantaka. Besides marking Lord Shiva's victory over demon Tripurasur, the celebration also honors Lord Kartik, son of Lord Shiva and a powerful warrior. In Varanasi, Dev Diwali is also the last day of Ganga Mahotsav, a festival that's particularly popular with tourists. It is an auspicious day during which devotees take a holy dip in the Ganges River and light earthen lamps called Diyas during the dusk of Kartik Purnima. There are millions of earthen lamps illuminating the steps of the Ganges Ghats. There are millions of lanterns in all temples in Benares as well.