A red thread known as Mauli or Kalava or Charadu is tied on wrist by Hindus before the beginning of a religious ceremony. The thread is tied on the right hand by males and on the left hand by females. The thread is tied to invoke the blessings of the Hindu deities especially of the particular deity to whom the puja is dedicated.
Legend has it that Lord Vishnu during his incarnation of Vamana tied a red thread on the hands of King Bali to grant him immortality and to rule the netherworld.
There is also a popular belief that the sanctified red thread with blessing of the deity protects a person from diseases, enemies and other dangers.