Tamil people, especially Hindus, observe Amavasai (New Moon) to perform rituals for their ancestors, seeking their blessings. According to the Tamil calendar, Amavasai occurs every month, but some Amavasai days hold special significance, such as Thai Amavasai, Aadi Amavasai, and Purattasi Amavasai (also known as Mahalaya Amavasai)
Thai Amavasai in 2025 falls on Wednesday, January 29 (தை-16, புதன்).
Aadi Amavasai in 2025 falls on Thursday, July 24 (ஆடி-08, வியாழன்).
Mahalaya Amavasai in 2025 falls on Sunday, September 21 (புரட்டாசி-05, ஞாயிறு).