Mangal Dosh Puja is one of the most important religious ceremonies performed in Ujjain, India. It is primarily a Hindu festival that celebrates the Hindu god Mars (Mangal). The puja is an elaborate ritualistic ceremony that includes chanting of mantras, offerings of flowers, fruits, and other items to the deities, and the burning of incense. It is also believed that Mangal Dosh Puja can help alleviate the suffering caused by the malefic effects of Mars, such as bad health, financial difficulties, and marital discord.

The main event of Mangal Dosh Puja is the offering of a special pooja called the "Mangal Dosh Yagya", which involves the invocation of the god Mars and the offering of prayers, sacrifices, and other items. After the puja, a special ritual called the "Mangal Dosh Havan" is conducted which involves the offering of incense and offerings to the gods.
The festival is celebrated in Ujjain for nine days and nights, concluding with a grand procession involving chariots, horses, and elephants. During the procession, the gods are offered prayers, offerings, and sacrifices. At the end of the procession, the Mangal Dosh Puja is performed.

The Mangal Dosh Puja is performed to ward off the evil influences of Mangal Dosh. It is believed that the Mangal Dosh can bring bad luck, health problems, and other misfortunes if left unchecked. The puja is believed to bring good luck and ward off the ill effects of Mangal Dosh.

The puja involves the chanting of mantras and offering of flowers, fruits, and incense. The devotees also perform a ritual bathing in holy water and offer prayers to the gods. At the end of the puja, a special offering of a coconut is made to the deity.

During the puja, a priest blesses the devotees and gives them a piece of cloth with a shawl. This cloth is believed to bring good luck and ward off the evil influences of Mangal Dosh.