Amavasya is the new moon day, the darkest night of the lunar month, marking the end of Krishna Paksha. While generally considered inauspicious for new ventures, Amavasya holds deep spiritual significance. It is the primary day for Pitru Tarpan (ancestor worship) and offerings to departed souls. Diwali, the biggest Hindu festival, falls on Kartik Amavasya. Mahalaya Amavasya (in Bhadrapada/Ashwin) is the most important day for ancestor rites. Somvati Amavasya (when Amavasya falls on Monday) and Shani Amavasya (Saturday) have special significance for Shiva and Shani worship respectively. The absence of moonlight makes this an ideal time for meditation, spiritual cleansing, and connecting with ancestral energy.