Kali Puja is celebrated on the new moon day, also known as Amavasya, of the Hindu month of Kartik, which typically falls in October or November.

Kali Puja is primarily observed to appease the goddess Kali and seek her blessings for protection, strength, and prosperity.

Goddess Kali is known as the goddess of destruction and transformation. She is often depicted as a fierce and powerful deity with a dark complexion, a protruding tongue, and a garland of skulls around her neck.

The main rituals performed during Kali Puja include offering prayers and flowers to Goddess Kali, performing aarti (ritual worship) of Goddess Kali, and sacrificing animals to Goddess Kali.

Animal sacrifice during Kali Puja is a symbolic offering to appease the goddess Kali and seek her blessings. It is believed that sacrificing animals pleases the goddess and brings good fortune and protection.

Traditionally, a goat is sacrificed during Kali Puja. However, in some regions, other animals such as buffalo, sheep, or chicken may also be sacrificed.

The red color during Kali Puja symbolizes the blood of the sacrificed animals, represents the fierce and powerful nature of Goddess Kali, and symbolizes the victory of good over evil.

The conch shell during Kali Puja is used to offer water to Goddess Kali, blown to announce the start of the puja, and used to create a sacred sound that pleases the goddess.

The fire during Kali Puja symbolizes the power of Goddess Kali, is used to offer food to the goddess, and is used to purify the offerings made to the goddess.

The drum during Kali Puja is used to create a rhythmic sound that pleases the goddess, announce the start of the puja, and accompany the singing of devotional songs.

The flowers during Kali Puja are offered to Goddess Kali as a symbol of devotion, used to decorate the puja altar, and used to create a fragrant atmosphere during the puja.

The sweets during Kali Puja are offered to Goddess Kali as a symbol of devotion, distributed among the devotees as prasad, and enjoyed by the devotees as a part of the festive celebration.

The music and dance during Kali Puja are performed to entertain the goddess, create a festive atmosphere, and express devotion to the goddess.

The immersion of the idol of Goddess Kali after the puja symbolizes the return of the goddess to her abode, marks the end of the puja festivities, and is a way to dispose of the idol in an environmentally friendly manner.

Kali Puja is celebrated with the most grandeur in the Indian state of West Bengal, where it is a major festival.