In Wireless Sensor Networks (WSNs), issues including energy management, topology management, bandwidth estimation, packet loss calculation, etc. are dealt. Only a few works have paid attention to mitigating congestion while estimating delay and bandwidth for transmitting data packets in WSNs. Several works on queue management and congestion control have incorporated Soft Computing (SC) techniques to solve some of the problems in WSNs. In this paper, an Active Queue Management (AQM) model to estimate congestion using Random Early Detection (RED) and mitigate congestion is proposed. It is found that the results obtained outperform the existing methods in terms of delay between intermediate nodes, end-to-end delay, packet loss ratio, packet loss probability, queue size and energy consumption.