The year 2020 was marked by the emergence of the COVID-19 pandemic. After months
of uncontrolled spread worldwide, a clear conclusion is that controlling the mobility of the general
population can slow down the propagation of the pandemic. Tracking the location of the population
enables better use of mobility limitation policies and the prediction of potential hotspots, as well
as improved alert services to individuals that may have been exposed to the virus. With mobility
in their core functionality and a high degree of penetration of mobile devices within the general
population, cellular networks are an invaluable asset for this purpose. This paper shows an overview
of the possibilities offered by cellular networks for the massive tacking of the population at different
levels. The major privacy concerns are also reviewed and a specific use case is shown, correlating
mobility and number of cases in the province of Málaga (Spain).
