In order to promote, sponsor, catalyze, conduct, and coordinate welfare services and development activities for the weaker sections of society, the Changanacherry Social Service Society (CHASS) was established. Besides its official role within the Archdiocesan setup, the Society has been granted NGO status under the charitable provisions of the Government Act (Travancore-Cochin Literary, Scientific & Charitable Societies Registration Act XII of 1955).

Founded in 1966, the Society has always been a pioneering organization in social innovations and research-based rural development services. The Society has a democratic setup, with its General Body consisting of village representatives, subject experts, and specially nominated individuals.

The Society operates in a large area in the south and south-central parts of Kerala, covering five districts: Kottayam, Alappuzha, Pathanamthitta, Kollam, and Thiruvananthapuram. This operational area is divided into 15 regions, comprising 164 local units for effective management and active involvement.