Onam has grown from a religious observance connected to Vamana's myth into Kerala's most important cultural festival, celebrated as the state's official harvest festival with public holidays, government-sponsored cultural programmes, and participation that extends well beyond religious observance into a broadly shared marker of Malayali cultural identity, embraced by Keralites of different faiths and by the large Malayali diaspora abroad. The ten-day festival is marked by several distinctive practices that have themselves become widely recognized cultural symbols: elaborate pookalam, intricate floral carpets laid out in courtyards and public spaces using flower petals arranged in geometric and pictorial designs, grow larger and more elaborate through the festival period; the onasadya, a large vegetarian feast traditionally served on a banana leaf and composed of a specific, substantial number of individual dishes, has become one of the most recognizable expressions of Kerala's culinary identity; and the vallam kali, competitive snake boat races on Kerala's backwaters using long, elaborately decorated boats crewed by dozens of rowers, draw large crowds and, in recent decades, television audiences.
Underlying this civic celebration remains the mythological premise the festival is built on: that Onam marks the annual homecoming of the good king Mahabali, sent to rule the underworld by Vamana's third step but permitted, in Kerala's version, to return each year to see that his former subjects still remember him, giving one of Hinduism's more theologically awkward stories, a god's defeat of a righteous king, its most warmly celebrated afterlife in the very region that keeps the defeated king's memory alive rather than the victorious god's.