Congestion is one of the several significant issues in wireless sensor networks that need proper attention. The wireless sensor networks may encounter unpredictable load when an event takes place. Congestion may occur when data packets arrive at node and there is no space in the buffer. Congestion may also occur when all sensors send the data at the same time. This causes wastage of limited energy, throughput reduction and loss and delay of packet. This paper presents a survey of traffic control and resource control mechanisms to control congestion in wireless sensor networks. It presents their significance, limitations and makes a comparison among them on the basis of various factors which would help in the future research and investigation in this particular area.