Priya Rajan, a 28-year-old woman, is the first Dalit and youngest mayor of India's fourth largest city, Chennai, which has a population of some 10 million.
Rajan is a postgraduate in commerce and was sworn in on March 4 as the 49th mayor of the city.
As a Dalit she is considered to be from one of the lowest caste groups who were once known as "untouchables."
She is said to be a member of the Evangelical Church of India (ECI), which has congregations in at least 10 states, UCA Catholic News reported.
Chennai, once known as Madras, is the state capital of the southern state of Tamil Nadu and is a center for education, health, information technology and the automobile industry.
Father Vincent Chinnadurai, the former spokesperson of the Tamil Nadu Bishops' Council, welcomed the appointment and said it was a remarkable moment for Dalit women.
"We appreciate the state government for this bold move. I am sure more women will feel inspired by Priya Rajan," he said.
India's 2,000-year-old caste system was officially abolished in 1950.
But the social hierarchy imposed on people by birth still exists in many aspects of life.
The caste system that defines people's place in society categorizes Hindus at birth, defining their position in society, the jobs they can do and who they can marry.
Chennai is considered the second-oldest city council in the world after London.
The Greater Chennai Corporation was formed in 1668 by the one-time East India Company, which founded it in 1640 as a trading post.
Tamil Nadu's ruling DMK (Dravida Munnetra Kazhagam or Dravidian Progressive Front) under the leadership of Chief Minister Muthuvel Karunanidhi Stalin, 68, won a landslide victory in the Feb. 19 elections after being an opposition group for 11 years.
Rajan, a member of DMK, is also the third woman to hold the mayor post and joins 10 women across the state who have been mayors and chairpersons in various small cities and towns.
Capuchin priest, Father Kulandai Swamy told UCA News: "It is an important milestone in Tamil Nadu's political history that a Dalit woman is being placed as mayor of this big city. It is a sign of empowerment of a marginalized community."
In Tamil Nadu, half the heads of city corporations and town municipalities positions are reserved for women and other marginalized groups.