Why is it celebrated?
Pongal is a Hindu harvest festival celebrated by Tamilians and people of Sri Lanka. The festival symbolizes the veneration of first harvest. Originally a festival of the farmers, Pongal is celebrated by everybody now. It is considered a very important festival for the people of Tamil Nadu and is celebrated according to the solar calendar.

Importance:
Pongal is the Tamil thanksgiving- This day is used to pay respect to our Almighty for keeping us in abundance. It is only after the celebration of Pongal that the new crop is harvested. It indicates the end of farming season, when farmers take a break from their routine and worship their crops. The festival honours sun and he is offered Pongal of milk and rice. To get a good harvest, it is necessary to appease the sun and rain Gods, as majority of rivers of this region are not perennial. So, sun is offered prayers for the same.  This day is also astrologically important, as the sun crosses Capricorn on this day.

How is it celebrated?
Pongal is celebrated for four days. The first day is Bhogi, when old clothes and wastes are burnt or thrown away, to indicate a new beginning. On the second day, milk is boiled in new pots in the morning, and is allowed to boil over. This tradition literally implies Pongal. People visit each other’s houses and exchange sweets. The third day is Mattu Pongal, when people thank their buffaloes and cows for sowing the land. On the last day, people celebrate by going out together. It is called Kanum Pongal. People offer spices, vegetables and sugar cane to their Gods. The offerings are then consumed by the devotees, as it is believed to purify them.