Diwali...this was my favourite festival while growing up....Its celebrated with Diyas. These Diyas are made of clay and can be decorated with various paints. In various temples and in homes, ghee or oil is used to light it up. Diyas are native to India and Nepal often used in Hindu, Sikh, Jain and Zoroastrian religious festivals such as Diwali (https://en.wikipedia.org/wiki/Diya_(lamp)).
In hindu religion,