Clock synchronization has paid a great magnitude of attention in the distributed systems. Sensor networks differ from traditional distributed system in many ways. One of the dramatic differences is the energy constraint in sensor network which is absent in traditional distributed systems. Almost any form of sensor data fusion or coordinated actuation requires synchronized physical time for reasoning about events in the physical world. Sensor networks make extensive use of time synchronized operations in many contexts (for example TDMA schedulers, synchronized sleep period, tracking and surveillance application). In this paper we propose a novel scheme for clock synchronization in sensor networks which is a combined idea of passive clustering and diffusion based asynchronous averaging algorithm for clock synchronization. Our proposed scheme takes the advantage of passive clustering for cluster creation and then applies asynchronous averaging algorithm for clock synchronization to reduce number of rounds and operations required for converging time which in turn save energy significantly than energy required in diffusion based asynchronous averaging algorithm.