close contact, maintaining good hand hygiene, and wearing cloth face coverings. In Japan and Taiwan, surgical masks have commonly been worn in winter months during the flu season by those who have respiratory illnesses as a courtesy intended to prevent viral transmission. Surgical masks provide some protection against the spread of diseases, and improvised masks provide about half as much protection. People in Japan as well as Korea and China may also wear masks in any season because of air pollution or allergies. Some younger Japanese people wear masks and audio headsets to signal a desire to avoid interaction. It has been suggested that mask-wearing as a custom appeared in East Asia rather than other parts of the world also facing pollution and disease due to the historical influence of Traditional Chinese Medicine and its ideas about air and wind. More recently, due to the rising issue of smog in South and Southeast Asia, surgical masks and air filtering face masks are now frequently used in major cities in India, Nepal and Thailand when air quality deteriorates to toxic levels. Additionally, face masks are used in Indonesia, Malaysia and Singapore during the Southeast Asian haze season. Air filtering surgical-style masks are quite popular across Asia and as a result, many companies have released masks that not only prevent the breathing in of airborne dust particles but are also fashionable. In Japan, some use masks as fashion statements, at times as a result of influence from K-pop stars. Surgical masks may also be worn to conceal identity. In the United States banks, convenience stores, etc. have banned their use as a result of criminals repeatedly doing so, but allowed facemasks due to the COVID-19 pandemic. In the 2019–20 Hong Kong protests, some protestors wore surgical masks amongst other types of mask to avoid recognition, and the government tried to ban such use. Research and development Researchers are developing face-masks which may help reduce viral spread better than existing ones and/or have possibly useful properties such as biodegradability or better breathability. Some are exploring whether attachments could be added to existing face-masks to make them more effective such as due to virus-deactivating fabrics or impregnations. The COVID-19 pandemic increased efforts to develop such masks. There also is an experimental face mask with an embedded biosensor that can detect a pathogenic signature (such as one of SARS-CoV-2) and face masks that glow under