It is an important festival particularly to the Vaishnavism tradition of Hinduism. Dance-drama enactments of the life of Krishna according to the Bhagavata Purana (such as Rasa lila or Krishna Lila), devotional singing through the midnight when Krishna is believed to have been born, fasting (upavasa), a night vigil (jagarana), and a festival (mahotsava) on the following day are a part of the Janmashtami celebrations.
It is celebrated particularly in Mathura and Brindavan, along with major Vaishnava and non-sectarian communities found in Manipur, Assam, West Bengal, Odisha, Madhya Pradesh, Rajasthan, Gujarat, Maharashtra, Karnataka, Kerala, Tamil Nadu, Andhra Pradesh and other regions.
In Tamil Nadu, the people decorate the floor with kolams (decorative pattern drawn with rice batter). Geetha Govindam and other such devotional songs are sung in praise of Krishna. Then they draw the footprints of Krishna from the threshold of the house till the pooja room, which depicts the arrival of Krishna into the house. A recitation of Bhagwadgita is also a popular practise. The offerings made to Krishna include fruits, betel and butter. Savories believed to be Krishna’s favorites are prepared with great care.
The most important of them are Seedai, Sweet Seedai, Verkadalai Urundai. The festival is celebrated in the evening as Krishna was born at midnight. Most people observe a strict fast on this day and eat only after the midnight puja. They also dress the youngest of male child in their family like Krishna and perform oonjal, or swing, which is rocked gently and prasadam offered first to them