When did Durga maa kill mahishasura?

Durga Maa killed Mahishasura during the festival of Durga Puja, which celebrates her victory over the buffalo demon. According to Hindu mythology, this battle took place over nine nights, culminating in the triumph of Durga on the tenth day, known as Vijayadashami or Dussehra. This victory symbolizes the triumph of good over evil. The story is narrated in various texts, including the Devi Mahatmya.