Certain states are tracking the mobiles of people who are under quarantine. Some examples of such states are Delhi, Andhra Pradesh, etc.
The government has released an official COVID-19 tracker app i.e. the AarogyaSetu app. It tracks the community transmission and traces the contact and travel history of individuals who are quarantined, using both location data and Bluetooth-based proximity tracking on users’ phones. Please follow this link to download it.