Janmashtami is celebrated to commemorate the birth of Lord Krishna, who is considered one of the most revered deities in Hinduism. Here are some of the main causes or reasons behind celebrating Janmashtami:

1. _Birth of Krishna_: Janmashtami marks the birth of Lord Krishna, who was born to Devaki and Vasudeva in Mathura.

2. _Victory of Good over Evil_: Krishna's birth symbolizes the triumph of good over evil, as he was born to defeat the demon king Kamsa.

3. _Divine Incarnation_: Krishna is considered a divine incarnation (avatar) of Lord Vishnu, who took human form to restore dharma (righteousness) on earth.

4. _Spiritual Significance_: Janmashtami is a reminder of Krishna's teachings and philosophy, which emphasize love, compassion, and selfless service.

5. _Cultural and Traditional Significance_: Janmashtami is an important part of Indian culture and tradition, with roots dating back to ancient times.

6. _Celebration of Love and Devotion_: Janmashtami is a celebration of the love and devotion of Krishna's devotees, who consider him their spiritual guide and mentor.

Overall, Janmashtami is a celebration of the divine, spiritual, and cultural significance of Lord Krishna's birth and teachings.