In cities there will be 75 Billion of connected IoT devices by 2030. The availability of IoT real time data through data exchange hubs holds the promise of making our cities smarter, safer, cleaner and more efficient. These are objectives we all share as citizens – but we do not want to give up control over our personal data to achieve them. The question then is – how can IoT and Data Privacy be reconciled? The unexpected answer is – with Blockchain. Blockchain will empower citizens to control access to their IoT live data, significantly increasing their trust & willingness to collaborate in making cities a better place to live.