-Taken from http://www.heb.gov.sg/mainhindufestivals.html#thaipusam -
Thaipusam which falls in the Tamil month of Thai (usually January/ February) is an annual procession by Hindu devotees seeking blessings, fulfilling vows and offering thanks. Thaipusam is celebrated in honour of Lord Subrahmanya (also known as Lord Murugan) who represents virtue, youth and power to Hindus and is the destroyer of evil.

The festival generally lasts two days. On the first day before Thaipusam, a statue of Lord Subrahmanya decorated with jewels and finery and together with his two consorts, Valli and Devayani, is placed on a chariot and brought in procession. In Singapore, the chariot procession begins from the Sri Srinivasa Perumal Temple at Serangoon Road to the Layan Sithi Vinayagar Temple at Keong Siak Road. The procession symbolizes the blessings sought by Lord Subrahmanya from his elder brother Lord Vinayagar.

Thaipusam ceremony starts in the early hours of the morning when the first batch of devotees of Lord Subrahmanya carrying milk pots and wooden kavadis leave Sri Srinvasa Perumal Temple for Sri Thendayuthapani Temple at Tank Road. The milk in the pots they carry are offered to the deity of Lord Subrahmanya at Sri Thendayuthapani Temple. Some devotees pierce their tongues with skewers and carry a garlanded wooden arch across their shoulders. Others devotees may carry a kavadi (semi circular metal structure decorated with peacock feathers, flowers and plam leaves). The spiked kavadis which require elaborate preparations leave the temple in the later part of the morning and continue till night.

Carrying kavadi is a popular form of devotion for Hindus. It is usually carried in fulfillment of a vow that a devotee would have taken. Placing a kavadi at the end of the foot procession at the altar of Lord Subrahmanya and making an offering of milk symbolizes the cleansing of the mind and soul and seeking of blessings.

In preparation for carrying a kavadi, a devotee has to prepare himself spiritually. For a period of about a month, the devotee must live a life of abstinence whilst maintaining a strict vegetarian diet. It is believed that only when the mind is free of material wants and the body free from physical pleasures that a devotee can undertake the sacred task without feeling any pain.