To stop harmful congestion spreading, lossless network needs much faster congestion detection and reaction than the end-to-end approach. In this paper, we propose a switch-level regional congestion mitigation mechanism (RCM) that performs traffic management just at the congestion region edge. RCM moves the end-to-end congestion control to hop-by-hop switch level to lower the congested region’s load as fast as possible. Meanwhile, to handle longer congestion, RCM detours the non-congestion flows to a light-loaded available path based on regional congestion degree to avoid the congestion region. Evaluation shows that the proposed RCM mechanism can perform timely congestion control over microburst flows, and achieve >10% improvement on mice flow’s FCT and throughput than DCQCN, with rarely performance reduction on elephant flows.