In Chinese or East Asian Calendar, one year is divided into 24 solar terms ( 节气). On the 104th day after winter solstice (冬至) is a solar term called Qing Ming (清明). It usually falls on the 5th day of April.
In ancient China, the emperors would use this day to pray to their ancestors and clean the ancestors’ mausoleum. This practice was followed by ordinary citizens and has since been passed down through generations as the day of honouring and paying respect to one’s ancestors and tending to their graves. This is also in line with the Confucian practice of ancestors’ worship, as part of Confucian rule of filial piety.
This is a cultural practice initially and was not meant to be a religious practice. However, since most Chinese are Taoists/Buddhists, they have adopted religious elements in praying to their ancestors, resulting in burning of hell papers, hell money etc.
Year in and year out, whenever I go to Nilai Memorial to pay respect to my own parents, I have seen a few Chinese families going to nearby graves with European daughter-in-laws or son-in-laws together to pay honour to the ancestors, without lighting joss sticks, but instead paying respect with flowers and of course tending and cleaning the grave. So this is a cultural tradition, and all Chinese, Korean , Vietnamese do pay respect to their departed ancestors on this day. This is also a day to remind us that without our ancestors, we would not be around.
In China, Hong Kong, Taiwan, this is a national holiday because in these societies, filial piety is considered the foremost important virtue of a person.
It also serves to remind us to treat our living parents with respect and love. All of us owe what we are today to our parents, and it is “important to remember the source of water when we drink it”, a Chinese proverb literally asking us not to forget our roots.