Congestion in wireless sensor networks creates a lot of issues like packet collision, buffer overflow, queuing delay and many to one data transmission scheme. This leads to degrade the quality of service parameters like packet delivery ratio, end to end delay and Average energy consumption of the wireless nodes. In this work is used to describe some of the congestion control mechanisms used in the WSNs and classifies them into four major categories traffic rate control, resource management, traffic rate and resource management and priority based congestion control. The comparative analysis is used to compare the popular congestion control protocols with each other in terms of congestion detection, congestion notification and its advantages and disadvantages.