When the Coronavirus pandemic spread across the world last year, the World Health Organisation (WHO) said that the SARS-CoV-2 (the virus that causes COVID-19) spreads primarily through small droplets expelled from the nose and mouth of an infected person that quickly sink to the ground. More and more research, however, emerged hinting at the possibility of airborne transmission of the virus. In an open letter to the WHO, published in the Clinical Infectious Diseases journal, 239 scientists in 32 countries outlined evidence that they say shows that floating virus particles can infect people who inhale them. Finally, in July 2020, the WHO had to acknowledge the different studies and reports.

This set in motion a new study in September 2020 by the CSIR-Centre for Cellular & Molecular Biology (CCMB) in India. CCMB director Rakesh Mishra says, “When a lot of significant data emerged about how the virus from an infected person can spread through air, we initiated this study. The question we had in our minds was—if it can travel through air, how long does it stay there for? How long can it spread? We wanted answers to these questions so that our government can come up with new guidelines to protect people from getting infected.”