CITYDATA measures the presence, density, and movement of people to build digital replicas for smarter cities and real-world businesses. CityData is a registered data broker that holds mobile device data rather than names or emails, so to delete your data you must email privacy@citydata.ai (or use their 'Do not sell or share my personal information' page) and supply your phone's advertising identifier (IDFA on iPhone, ADID on Android). They aim to reply within 45 days but say complex requests can take up to 90 days, and identity verification is done for website visitors/customers. To stop future collection, disable location sharing/ad tracking or reset your advertising ID, since data can be re-collected from apps using their SDK.