With continuous increase in urban population, the need to plan and implement smart cities based solutions for better urban governance is becoming more evident. These solutions are driven, on the one hand, by innovations in ICT and, on the other hand, to increase the capability and capacity of cities to mitigate environmental, social inclusion, economic growth and sustainable development challenges. In this respect, citizens’ science or public participation provides a key input for informed and intelligent planning decision and policy making. However, the challenge here is to facilitate public in acquiring the right contextual information in order to be more productive, innovative and be able to make appropriate decisions which impact on their well being, in particular, and economic and environmental sustainability in general. This study present a Cloud-based architecture for context-aware citizen services for smart cities and walkthrough it using a hypothetical case study.