New WSJ report found that 'Near Intelligence', a consumer data broker based in India, Singapore and the US with an office in France, obtained massive amounts of smartphone geolocation data via digital advertising firms like OpenX, Smaato and AdColony and sold it to US defense and intelligence agencies.
Near claims to have access to data about 1 billion mobile devices.
https://wsj.com/tech/cybersecurity/how-ads-on-your-phone-can-aid-government-surveillance-943bde04
WSJ · How Ads on Your Phone Can Aid Government SurveillanceFederal agencies buy bulk data, collected from ads you might never see, that can yield valuable information about you