The IoT is described as a smart interactive environment where devices communicate together ubiquitously sometimes in the background, performing functions on behalf of the users and offering many advanced services to them. Examples range from simple smart home applications such as ambient intelligence and remote controlling functionalities to more advanced smart cities setups. A smart IoT city for instance will encompass a network of many interconnected networks where various sensors and actuators distributed across many areas of the city share information, create knowledge and trigger actuation events. In such a dynamic and rich environment, it is vital for security to trace the source of data and verify its origin. This where data provenance in the IoT come to play. This work attempts to explore requirements and applications of data provenance in the IoT and the challenges pertaining to its realisation.