From using sanitisers to virus-killing UV technology, to use of HEPA filters to clean the air there has been a constant effort to make our homes and workplaces safer since the coronavirus pandemic started. NDTV talks to Ravi Kaushik, an alumnus of IIT-Bombay and Chief Executive Officer of AirTH, who, along with others, has made a kind of "antimicrobial air purifier" that offers protection from airborne disease transmission and air pollution. It even claims to help fight the spread of coronavirus.