This episode comes at a critical juncture when we are still pondering ways in which the lockdown can be lifted in a calibrated manner in some areas while being extended in others as the battle to contain the spread of COVID-19 in India continues. There are crucial questions to be asked about how to contain the virus if the lockdown is lifted, what kind of data we may need to determine the spread of the virus in the population and how to balance the costs of an extended lockdown with the economic fallout. Mathematical modelling is essential to chart a course forward and frame policy around these questions and we try and break down some of these concepts in this conversation. Guest: Dr. Gautam Menon, Professor of physics and biology, Ashoka University. Researcher on the modelling of infectious diseases and its implications for public policy (Recorded on April 11, 2020) Write to us with comments and feedback at socmed4@thehindu.co.in