It is celebrated on the occasion of uttarayan  (northward journey) of the Sun-god. A special semi-liquid preparation called Makara Chaula is offered to the god as prasad and distributed among one and all. (Makara Chaula is prepared by combining semi-pasted rice, milk, scrubbed coconut, banana, chopped cucumber, cottage cheese, sugar, ginger and black pepper - all stirred together).

(Source - Oriyanari.com)