Praise-HK is a smart city app that provides real-time and forecasted air quality and health risk information at street level in Hong Kong. The team is comprised of scientists from the Institute for the Environment at the Hong Kong University of Science and Technology (HKUST). Praise-HK was looking for suitable vendor for the development of the mobile app given that the sophisticated technical requirements on product development. The requirements include incorporation of real-time location tracking, personalised content, as well as health advisory features. By adopting an agile project management approach, Gianthouse was able to manage the entire development cycle and met stage delivery goals of the client. We also collaborate with another technical service provider that is specialised in mobile geo-location technology. Throughout the product development process, we modularized the functions and tasks in order to prepare for the project to add features and expand into other regions in the future.