Onam - the traditional harvest festival of Kerala

Pookolam, with flowers. patrikai.com
The annual harvest festival varies from region to region in India, depending on the timings of harvest and crop patterns. It is a sort of thanks-giving festival dedicated to the almighty for a successful harvest  by providing copious supply of rain and optimal weather condition for raising the crops.  India is a land of many festivals and many are native to their respective  states.  Across India, almost every month there will be some kind of festival related to the religion, example:the Durga Puja of West Bengal, Ganapati Chaturthi of Maharastra.. These various colorful festivals offer a kaleidoscopic view of our culture that is well-knitted with religion. No matter where they live people hold the festivals to their heart and celebrate them with enthusiasm and devotion. If you go deep down to the roots of many of these festivals the matrix is ''spiritual''.   In no other country on this planet you can see so many colorful festivals at  their best  as in India. In southern India Pongal or Sankaranthi and Onam festivals are  popular and associated with harvest seasons. 
As for Onam festival which is a 10-it day event, is held on a grand scale in the southwestern state of Kerala. It showcases the unique   culture and heritage of this state  which is often dubbed as ''God's own Country''. The state  government declares three or four official  holidays. Starting from Onam Eve (Uthradom) to the Third Onam Day, the festival  falls during the Malayalam month of Chingam (August or September) and it marks the annual home coming of the mythical King Mahabali who is believed to be the king of Kerala. A colorful rally accompanied by floats and folk dance performances  mark the ‘Athachamayam’ celebrations, heralding the start of the 10-day ‘Onam’ festivities in Kerala.

Mahabali, though charitable, was egotistical on account of powerful boons he received from the God. To subdue his arrogance and ego, Vishnu in the guise of a dwarf saint ''Vamana'', approached the king for charity and asked him to grant him a small piece of land equal to his three strides. Thinking it was a simple grant, the king agreed. Now Vamana turned into a giant and measured the earth and the sky with two strides. As there was no place for the third stride, King Mahabali stuck to his word and offered his head. Vishnu put his foot on him and pushed him into  the underworld. 
In reality, God was quite pleased with his integrity and offered 
him salvation by keeping him close to his place. The king requested
the lord to allow him to visit his land Kerala once a year on Thiruvonam (the second day of Onam) to visit his people to make sure they were doing well, to which the lord agreed.  
Vallam Kulangara - Snake boats wikipedia.

 With a view to giving King Bali  warm and impressive reception, for his annual visit, the people of Kerala clean and decorate their homes with floral displays. Besides, ladies make  Pookkalam - rangoli on the ground in front of their homes. The kolams made of flowers of various colors are attractive, as they have mind-boggling geometric patterns.  Yet another interesting feature is before most of the well-decorated Hindu temples, one can see many caparisoned elephants. During the festival time lasting 10 days, particularly after evening performing artists, well trained under prominent Gururs,  perform state's traditional  dances such as Kathakali, Mohiniyattam.  Part of Onam festival includes impressive Ona Thallu, a martial art native to Kerala, Puli Kali (tiger dance),Thambi Thullal (women's dance)  Vallam kali snake-boat races that are held at Champakulam. The boat race in Aranmula is yet another major attraction of the festival. Children get attracted by the procession of well-decorated and caparisoned elephants during this festival time.  Away from mundane stuff, giving a rhythmic touch to the religious procession, percussionists perform Chendamelam and panchavadyam (local percussion instruments)in a grand way, exhibiting their talents.
Traditional Onam sadhya is served on banana leaf. (Source: Getty Images/Thinkstock)
 Above image:   Traditional ''Onam Sadhya'' is quite famous and is cooked in all households. There is no doubt that the mouth-watering array of food will tickle your hungry tummy. Spread on plantain leaves, the meal includes nine courses, but may include over two dozen dishes, including chips (especially banana chips), Sharkaraveratti (fried pieces of banana coated with jaggery), pappadam, various vegetable and soups such as injipuli (also called puli inji), thoran, mezhukkupuratti, kaalan, olan, avial, sambhar, dal served along with a small quantity of ghee, erisheri, molosyam, rasam, puliseri (also referred to as velutha curry), kichadi (not to be confused with khichdi) and pachadi (its sweet variant), moru (buttermilk or curd mixed with water), pickles both sweet and sour, and coconut chutney. The big feast ends with dessert called Payasam (a sweet dish made of milk, sugar, jaggery, and other traditional Indian savouries) eaten either straight or mixed with ripe small plantain.  Even if you  take a look at the payasam, it will make your mouth dribble. The curries are served with parboiled rice-‘Kerala Matta’. Parboiled rice is widely used in Kerala. The semi-polished brown rice of Kerala used in Sandhya feast is known as kutthari. (https://indianexpress.com/article/lifestyle/food-wine/onam-special-onam-sadhya-recipes-inji-puli-5969503-kerala/)

People of other religions participate in this popular festival and partake of sumptuous food specially prepared for the festivals.  Private banks and institutions in the state give following month's salary in advance so that employees can celebrate the festival with joy. During this period Hindu temples are crowded with devotees and at famous temples traditional dance performances can be seen in the Koothambalam (Natya mandapa) - space for dance on the temple premises.