Daya Bai was born as Mercy Mathew on 22 February 1940 in a prosperous Christian family in Pala, Kerala. She had a happy childhood with a strong faith in God. At the age of 16, she left her home to become a nun. However, her calling had been different, and she left to work for the tribal population in the midlands of India.
Daya Bai has been delivering inspirational speeches and holding satyagrahas and campaigns to compel the local authorities to open schools and empower the neglected villages in the interior and tribal Madhya Pradesh. Apart from her solo struggles representing the forest dwellers and villagers in Madhya Pradesh, Bihar, Haryana, Maharashtra, and West Bengal, she was also associated with Narmada Bachao Andolan and the Chengara agitation.
Daya Bai resides in the Barul village of Chhindwara district in Madhya Pradesh and set up a school there. As a tool for the eradication of poverty, Daya Bai started the Swayam Sahayatha Group in the late 90s. in January 2012 she was awarded the Good Samaritan National Award instituted by the Kottayam Social Service Society and Agape Movement, Chicago. Shiny Benjamin made a one-hour-long documentary on Daya Bai named Ottayal or ‘One Person’.