Wireless sensor networks sense various kinds of information process them locally and communicate it to the outside world via satellite or Internet. In the near future, sensor networks will play a major role in collecting and disseminating information and the sensors will be shared by multiple applications and gather heterogeneous data of different priorities. With such concentration on wireless sensor networks, vital issues like security and congestion control are to be taken care of. The authors propose Modified Secure Congestion Aware Routing Protocol (MSCARP), a protocol designed for mitigating congestion by dedicating a portion of network to forward high-priority traffic primarily by measuring congestion degree as the ratio of packet interatrial time along over packet service time and provide a better in terms of the packet loss rate and packet delay.