Aarogya Setu, the COVID-19 tracking app launched by the Government of India calculates data based on a person's interaction with others, using bluetooth, algorithms and Artificial Intelligence. The government's target: 30 crore downloads in next few weeks. NDTV's Sanket Upadhyay speaks exclusively to Lalitesh Katragadda, the Advisor to the government on the Aarogya Setu app.