Diwali, also known as the Festival of Lights, is celebrated to mark the return of Lord Rama to Ayodhya after completing his 14 years of exile. According to the legend, the people of Ayodhya welcomed him by lighting lamps made of ghee, celebrating his homecoming. Since then, Diwali has been celebrated, with people lighting lamps and worshiping Lord Ganesha and Goddess Lakshmi for prosperity and well-being.

However, Diwali is not celebrated in certain regions of India. In the state of Kerala, Diwali is not widely observed, although it is celebrated with grandeur in the city of Kochi. Additionally, in parts of Tamil Nadu, Diwali is not a major festival.

https://www.nayaindia.com/life-style/diwali-2024-diwali-is-not-celebrated-in-this-state-of-india-know-the-reason-475825.html