The speaker shall share the experience of his team in exploring the possible dominant transmission route of SARS-CoV-2 and associated intervention in the past 12 months. Their work may be divided in three parts, i.e. investigating outbreaks in Mainland China in early 2020, which provided the essential probable evidence for the recognition of airborne transmission by WHO and US CDC in October 2020, investigating vertically aligned outbreaks in Hong Kong and Guangzhou, suggesting the possible roles of drainage leakages and faecal aerosols, currently not recognized by WHO, and developing a dominant short-range airborne theory and associated building ventilation needs for WHO, and the work seems to provide an explanation why some heavy or moderate activity venues such as gyms, bars and meat processing plants have had higher attack rates.