An Indian artist applies color on earthen lamps ahead of Diwali festival in Calcutta, India, Oct. 25, 2016. Diya is a small earthen lamp primarily lit during Diwali, the Festival of Lights. Also known as ‘deep’, diya is traditionally made of clay. During Diwali, the earthen lamps are used for illuminating the entire home and premises. The diya is filled with ghee or oil.