Understanding Kavady

Carrying a kavadi is regarded as the ultimate show of devotion to Murugan, a very special sacrifice. In fact, kavadi translates as ‘a sacrifice with every step’. In turn, the carriers ask a favour of Murugan, like the fulfilment of a wish or the curing of a sick family member. Others show their gratitude for a boon granted.

As with all Hindu festivals, the origin of Thaipusam is based on an ancient legend. Once upon a time, the saint Agastya was in need of some special plants to perform religious sacrifices. The plants were growing only on the mystical mountains Shaktigiri (Mountain of Goddess Shakti) and Shivagiri (Mountain of Lord Shiva). The saint asked his servant Idumban to fetch him the mountains, so that he could pick the plants himself. Idumban, trusty servant that he was, lifted both mountains and tied them to the ends of a pole. Then he shouldered the pole, carefully balancing the mountains. As he was going along, invisibly, Murugan sat down on one of the mountains, making the load too heavy for poor Idumban. Desperate to fulfil his chore, Idumban began to pray fervently to Murugan, asking him for strength to carry on. After a while, the god appeared to him. Murugan promised that from now on everybody who showed his devotion by carrying a heavy load and who sacrificed sandalwood, milk and flowers, would be blessed.

According to a rival legend, Idumban was a demon, who stole the mountains, only to be defeated in battle by Murugan.

Reference: http://www.cpamedia.com/articles/20060622_03/