What is the relationship between Tomb-Sweeping Day and Taoism?

It doesn't matter. Tomb-Sweeping Day is a traditional festival of Han nationality in China. Tomb-Sweeping Day began around the Zhou Dynasty. Grave-sweeping is very popular in Tomb-Sweeping Day. In fact, sweeping graves is the content of Tomb-Sweeping Day's Cold Food Festival the day before. It is said that cold food originated in Jin Wengong to mourn Jiexiu. During the twenty years of Emperor Xuanzong's reign, he ordered the world to "eat cold food in the ground". Because cold food is associated with Qingming, it gradually spread to sweeping graves in Qingming. Moreover, there is no Tomb-Sweeping Day in the main festivals of Taoism.