Why can we only break the civil graves on the solstice in winter?

On the solstice of winter, Shangrao people call it "Winter Festival", and folk customs regard this day as ancestor worship day, inviting ancestors to burn incense to worship their ancestors and move their graves. Winter solstice, July 30th, Qingming can be described as a gathering of Yin and Yang. The solstice in winter is the day to move the grave, and the grave soil cannot move normally, otherwise it is taboo. Only when the winter solstice is clear can the ground be broken, unless it is now a notice to move the grave in the development zone and move within a time limit. Children and grandchildren can't move their graves until the solstice of winter, and it is very solemn to move their graves. First, they lit incense and told the dead underground: I will move for you. Then drink a few mouthfuls of soju to drive away the yin in the grave, dig the grave, and if the coffin is not rotten, take it out and pick up the bones with a crock. Then set off firecrackers, which means "moving". After the bones of the deceased are transported to a new cemetery, they are dug and buried, carved on trees and set off firecrackers, which means "settling down".