At that time, the Bengal state (covering the entire Eastern part of British India) was a mission area entrusted to the Belgian Jesuits.
While teaching in the schools of Rengarih and Ranchi (1911–16), both important centres in the (now) Jharkhand state (India), Sevrin had his first contacts with the aboriginal population of the Chota Nagpur plateau.
He promoted also the local press by creating the Hindi language magazine called Nishkalanka and composed a little catechism and other booklets (among them the Bible ka Itihas) in order to build up a faith culture among the many new Christians of his diocese.
He was giving two reasons: there was a local Oraon priest, Nicolas Kujur, who, Sevrin felt, was quite capable of taking his place as the pastor of the diocese, and, second, he wanted to go to a neighbouring state where conditions of missionary work – because of great hostility towards Christianity – were extremely difficult.
His new diocese, Raigarh-Ambikapur (newly erected), was formed of several little princely states where, as long as they were autonomous (till the independence of India in 1947), the presence of Christian missionaries was strictly prohibited.