Mother Teresa of Kolkata remains one of the adopted figures of the old Indian capital in that after her arrival to be a teacher in a well-to-do school in Kolkata she took to the slums and the service of the ‘poorest of the poor’ within an independent India. While there are several works published about her life after she opened Nirmal Hriday Ashram, a home for the destitute and the dying in Kolkata, less has been researched on the female Hindu symbolic associations of Kolkata with the feminine, as well as the challenges that Mother Teresa faced when as a Christian and as a woman decided to open Nirma Hriday Ashram. This paper examines the significance of Kālighāt for Kolkata and Hinduism and the issues of (in)purity that were triggered by Mother Teresa’s opening of a place for the dying within a property that previously was part of the Kālighāt. This paper suggests that a socio-historical understanding of Kolkata is central to any understanding of the work of the Missionaries of Charity in Kolkata in later periods and their ongoing cooperation with Hindus and Muslims within Kolkata. Thus, ritual purity is not an isolated understanding within a synchronic moment but a generational challenge to ongoing diachronic changes within the City of Kolkata.