Context aware computing utilizes the information embedded in physical and computational environments to provide services adaptive to users? preferences. As these services become more pervasive, the need for a service delivery mechanism arises. Due to the diversity, magnitude and nature of the contextual information, a context-based service delivery mechanism is required which can not only identify the most appropriately matching services for the interested clients but can also ensure that the contextual information is not compromised by providing services to illicit consumers. This paper focuses on the issues of service delivery in pervasive computing environments where services and clients are vast, varied and completely decoupled from each other. Semantics-based attributes are used for service registration and lookup. Privacy is maintained by incorporating policy based access control mechanisms in the service delivery modules.