I don't know why I was denied entry and deported, and so I can only speculate on the possible reasons. Clearly it was not about visa irregularities because there was a one-year multiple entry research visa expiring well after my planned departure from India on 7th April stamped on my passport.
I am also sure that the decision taken by the Indian immigration authorities is not due to the possible controversial or sensitive nature of the research I am currently undertaking in south Kerala, the reason for my current visit.