At the beginning of 2020, the world woke up to a nightmare. The COVID-19 pandemic began. On January 30, 2020, the World Health Organization (WHO) declared a "Public Health Emergency of International Concern" (PHEIC). None of us was prepared for such a thing. Governments were also surprised. Faced with death reports from all over the world, the seriousness of the situation became clear. Measures began to be taken on a global scale.

This was the first time the world had experienced such a global catastrophe in modern times. We knew that in the past, when the world's population was not so large, and a large part of the population lived in rural areas, epidemics claimed many lives. But in today's world, where people travel side-by-side, shoulder-to-shoulder, where thousands of people stand nose-to-nose on public transport such as buses and trains, and where there is a ri