An emissions cleaning module comprising: i) an upstream conduit containing a diesel oxidation catalyst module; ii) a downstream conduit; iii) a further conduit, downstream of the downstream conduit containing a selective catalytic reduction module for converting ammonia and NOx to diatomic nitrogen (N 2) and water (H 2 O); iv) a flowhood that functions as a flow directing component fluidly connecting an outlet of the upstream conduit with an inlet of the downstream conduit; v) an injector module mounted to the flowhood and configured to inject a urea solution which decomposes into ammonia; and vi) a mixer configured to mix exhaust gas and ammonia, the mixer comprising: a) an elongate body located within the flowhood and the downstream conduit, an upstream end of the elongate body being open to receive urea injected from the injector module; and wherein the upstream end of the elongate body is configured to be mounted to the flowhood; and wherein the upstream end of the elongate body is configured to be mounted over an outlet of the injector module; and b) a plurality of apertures configured to permit passage of exhaust gas therethrough; wherein the elongate body comprises a plurality of scavenging holes at, or towards, an upstream end of the elongate body; and wherein the elongate body is provided with an un-apertured region between the scavenging holes and the plurality of apertures; wherein the plurality of scavenging holes, in use, allow for a swirling flow of exhaust gas to pass in the vicinity of an outlet of the injector module to help prevent build-up of deposits of urea on or near the outlet of the injector module. i) an upstream conduit containing a diesel oxidation catalyst module; ii) a downstream conduit; iii) a further conduit, downstream of the downstream conduit containing a selective catalytic reduction module for converting ammonia and NOx to diatomic nitrogen (N 2) and water (H 2 O); iv) a flowhood that functions as a flow directing component fluidly connecting an outlet of the upstream conduit with an inlet of the downstream conduit; v) an injector module mounted to the flowhood and configured to inject a urea solution which decomposes into ammonia; and vi) a mixer configured to mix exhaust gas and ammonia, the mixer comprising: a) an elongate body located within the flowhood and the downstream conduit, an upstream end of the elongate body being open to receive urea injected from the injector module; and wherein the upstream end of the elongate body is configured to be mounted to the flowhood; and wherein the upstream end of the elongate body is configured to be mounted over an outlet of the injector module; and b) a plurality of apertures configured to permit passage of exhaust gas therethrough; a) an elongate body located within the flowhood and the downstream conduit, an upstream end of the elongate body being open to receive urea injected from the injector module; and wherein the upstream end of the elongate body is configured to be mounted to the flowhood; and wherein the upstream end of the elongate body is configured to be mounted over an outlet of the injector module; and b) a plurality of apertures configured to permit passage of exhaust gas therethrough;