K. VijayRaghavan, the Principal Scientific Advisor to the Government of India, tweeted on May 15, stressing on not just masks and physical distancing, but also ventilation as a precaution against Covid-19. Dr Rommel Tickoo, director - internal medicine at Max Healthcare, explains the importance of ventilation given the evolving understanding of how the Sars-CoV-2 coronavirus spreads. Watch the full video for more.