Investigating population dynamics of the Kumbh Mela through the lens of cell phone data

The Kumbh is a religious Hindu festival that has been celebrated for centuries. The 2013 Kumbh Mela, a grander form of the annual Kumbh, was purportedly the largest gathering of people in human history. Many of the participants carried cell phones, making it possible for us to use a data-driven approach to document this magnificent festival. We used Call Detail Records (CDRs) from participants attending the event, a total of 390 million records, to investigate its population dynamics. We report here on some of our preliminary findings. Introduction The Kumbh Mela is a religious Hindu festival that has been celebrated for hundreds of years. On the broad sandy flats left behind by the receding waters of the rainy season, a temporary “pop-up” megacity is constructed in a matter of weeks to house the festival. The Kumbh Mela has evoked endless fascination and scrutiny by observers dating back to Chinese and Arab itinerant scholars from centuries past, to contemporary academics, mostly social scientists and humanists of various disciplinary persuasions. Both participants and external observers have documented past Kumbh festivals, and this book brings together various perspectives using different methodologies to the study of the 2013 Kumbh Mela. In this chapter, we examine the use of cell phone communication metadata to study the 2013 Kumbh Mela. Telecom operators worldwide collect these data routinely for billing and research purposes. At bare minimum, metadata contain information on who calls whom, at what time, and for how long. The metadata studied here, also known as Call Detail Records (CDRs), were made available to us by the Indian telecom operator Bharti Airtel for the period from January 1, 2013 to March 31, 2013. The cohort we introduce here consists of all Bharti Airtel customers who were present at the Kumbh Mela site during this time period and used their cell phone at least once to communicate with