In WSN congestion occurs when traffic load exceeds the capacity available at any point in a network. Congestion acts an important role in degrading the performance of the network or failure of the network. So it is essential to detect and control the congestion in the entire WSN. Thus one can improve the performance of the network. Different factors are involved in the congestion; the main factor is buffer over flow, packet loss, lowers network throughput and energy wastage. To address this challenge this is essential for a distributed algorithm that mitigate congestion and allocate appropriate source rate to a sink node for wireless sensor network. This paper gives some ideas how to control and manage the congestion in a wireless sensor network.