In an open letter due to be published this week, a group of scientists call for greater acknowledgement of the role of the airborne spread of Covid-19. Nobel Laureate Mario Molina, who endorses the letter, told Newshour that he believes that aerosols play a significant role in the transmission of the virus.Also in the programme: Who’s behind the growing list of Chechen dissident killings? And we report on US race relations during the legacy of the Obama era.(Photo: Man with mask in Barcelona. Credit: European Photopress Agency)