Why do people carry candles during the St. Lucy's Day celebration?

Saint Lucy, December 13th, is connected to the candle tradition because according to legend the saint carried a lit lamp while distributing food to persecuted Christians in the catacombs. The most famous depiction of her shows her holding a candle, often in a crown on her head, and this symbol became so deeply rooted in tradition that in Nordic countries especially (Sweden, Norway) Lucy processions feature girls wearing crowns of lit candles.

Light thus represents hope during the darkest period of the year, since December 13th is one of the shortest days before the winter solstice. Carrying candles during the celebration is a way of honoring this symbolism: the saint as a bearer of spiritual and literal light. In Italy the tradition is less widespread than in Northern Europe, but in many places you still see processions and performances with lit candles, even though many churches have had to switch to fake candles for safety reasons.