According to Hindu mythology, Lord Muruga was born as six different babies. And he was looked after by the six Krittika stars. Later, Lord Muruga was combined as a single baby with six heads by Goddess Parvati. There are many variations to this legend.
The Krithigai star or Nakshatram is considered highly auspicious to worship Muruga. And Aadi Krithigai is more important because Aadi is the first month in the Dakshinayana punyakalam – when the sun god changes his direction from north to south.
Devotees carry flower Kavadi on the Aadi Krithigai day. It is celebrated in a grand way with various rituals in Murugan temples across the world.