Atham is the first day of grand Onam celebration. The Atham day falls in the month of Chingam according to the Malayalam calendar. On this day, it is largely believed that King Mahabali who ruled once in this region starts his personal preparation to descend to Kerala from heaven. The Thrikkakara Temple is considered by the Hindu religious scholars as the abode of Mahabali. Atam day also marks the start of festivities at this particular temple. In 2012, Atham during Onam festival is August 21.
A grand colorful procession at Thrippunithura near Kochi starts off as a mark of the Onam celebrations across the state and this procession is known as Athachamayam. It is to be remembered that during the olden days in the Kochi region, the Kochi Maharaja usually used to lead a military in full ceremonial robes and grand uniformly colorful procession from his royal palace to the nearby Thrikkakara Temple.
The public took over the function after independence and started celebrating as the official celebrations of Onam which is considered also as a major cultural procession which kicks off as festivity procession across the other part of the state. Athachamyam is made as a spectacular event with the indulgence of folk art presentations, elephant processions, music and dancing by troupes. This event is now aggressively and annually promoted as a tourist event.
It is on Atham day, Pookalam, the traditional ritual of laying floral carpet colorfully starts on. Athapoo is the name given to the size of pookalam on this particular day. The first day’s small Athapoo eventually grew day after day to a larger size. These floral carpets add attraction to the front verandah and inner halls of the house. It is to be noted that only bright and slight yellow flowers are used on the floral carpet on this day. The floral design used is also very simple. It is to be noted that the statues of King Mahabali and Vamanan are installed on the junction of the road and at the entrance of each house on this particular day.