In Wireless Sensor Networks (WSNs), congestion plays an important role in degrading the performance of the network. Under idle condition, the network load is very low whereas when an event is detected the network load becomes high which leads to congestion. Due to congestion, the overall performance of the network degrades. Hence, it is necessary to detect and control congestion. In this paper, an efficient technique to detect and control congestion has been proposed. The congestion is detected by calculating a metric called Congestion degree (Cd). It is the ratio between packet inter arrival time and packet inter service time. Once the congestion is detected, it is notified using Implicit Congestion Notification (ICN) signaling.