Some notes to put in a blog – from Christianity in India by Leonard Fernando G. Gispert-Sauch. I am putting the notes in my own words.
Speaking on a more external anthropo-socio-logical level
1. The desire to be free from Caste and Feudal oppression.
2. The realization that there were increasing opportunities for upward mobility if they would only take advantage of them.
3. The spread of education made them more aware of the injustices that they were suffering.
4. Social protest.
On a more religious level:
1. Coming to an accurate knowlege of the contents of the Bible.
2. Finding something attractive in Jesus Christ, in particular being able to resonate with His sufferings.
3. Finding the message of the Gospel compelling.
4. Being part of a community of faith.
5. The wonderful experience of worshipping God.
6. The sense of belonging attained when partaking of the Eucharist.