Italy: Lombardy tests lockdown compliance by analysing cellphone data 

Using mobile phone data to verify the movements of their owners, the Italian region of Lombardy found that between February 20, when the first COVID-19 case was discovered, and March 10, movement by its 2 million inhabitants dropped by just under 60%. Lombardy has also used cell phone data, obtained from the telecommunications companies and transferred to the ISI Foundation for a public impact research project, to monitor how many people move around the district. Because of privacy laws, the system does not surveil individual phones, but calculates overall movements, taking into account allowed excursions such as work and health needs. The country was locked down on March 9.
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Sources:

https://www.nextquotidiano.it/lombardia-controlla-gli-spostamenti-dei-cittadini-con-i-cellulari/
https://www.regione.vda.it/notizieansa/details_i.asp?id=338579

Writer: Alessandro D'Amato; ANSA

Publication: Next Quotidiano; Valle d'Aosta