Mangal Dosh Puja in Ujjain is performed to mitigate the adverse effects of Mangal Dosha in a birth chart. Ujjain, a city of immense spiritual importance, hosts this puja to appease Mars (Mangal) and reduce its malefic influence. The ceremony involves rituals, prayers, and offerings, helping individuals overcome challenges in marriage, career, and health, ensuring a harmonious and prosperous life.