A system for use with an internal combustion engine configured to produce an exhaust gas flow, the system comprising: an exhaust gas passageway, at least a portion of the exhaust gas passageway comprising: a primary passageway (230, 630, 830); an injector passageway (224, 408, 508, 608, 808) adjacent to, and sharing a first divider wall with, the primary passageway (230, 630, 830), the first divider wall including an injector aperture, the injector passageway (224, 408, 508, 608, 808) comprising a portion that is located at a bend (304, 604); and a reductant injector exposed in the primary passageway (230, 630, 830) through the injector aperture, an end of the reductant injector in a flow path defined by the injector passageway (224, 408, 508, 608, 808), the reductant injector configured to release a reductant into the primary passageway (230, 630, 830) and a catalyst located downstream of the reductant injector, the catalyst configured to receive a primary flow through the primary passageway (230, 630, 830), the primary flow mixed with the reductant; the system being characterised in that the portion of the exhaust gas passageway further comprises: a bypass passageway (222, 618, 818) adjacent to, and sharing a second divider wall with, the primary passageway (230, 630, 830), the second divider wall and the first divider wall located at opposite sides of a centerline of the primary passageway (230, 630, 830); and in that the reductant injector is configured to release a reductant towards the bypass passageway (222, 618, 818). an exhaust gas passageway, at least a portion of the exhaust gas passageway comprising: a primary passageway (230, 630, 830); an injector passageway (224, 408, 508, 608, 808) adjacent to, and sharing a first divider wall with, the primary passageway (230, 630, 830), the first divider wall including an injector aperture, the injector passageway (224, 408, 508, 608, 808) comprising a portion that is located at a bend (304, 604); and a primary passageway (230, 630, 830); an injector passageway (224, 408, 508, 608, 808) adjacent to, and sharing a first divider wall with, the primary passageway (230, 630, 830), the first divider wall including an injector aperture, the injector passageway (224, 408, 508, 608, 808) comprising a portion that is located at a bend (304, 604); and a reductant injector exposed in the primary passageway (230, 630, 830) through the injector aperture, an end of the reductant injector in a flow path defined by the injector passageway (224, 408, 508, 608, 808), the reductant injector configured to release a reductant into the primary passageway (230, 630, 830) and a catalyst located downstream of the reductant injector, the catalyst configured to receive a primary flow through the primary passageway (230, 630, 830), the primary flow mixed with the reductant; the system being characterised in that the portion of the exhaust gas passageway further comprises: a bypass passageway (222, 618, 818) adjacent to, and sharing a second divider wall with, the primary passageway (230, 630, 830), the second divider wall and the first divider wall located at opposite sides of a centerline of the primary passageway (230, 630, 830); and in that the reductant injector is configured to release a reductant towards the bypass passageway (222, 618, 818).