Clearances was about his mother's death. Being the oldest of nine children and having experienced sibling death early in the family, he had a special bond with both his parents and, as we see in this poem, particularly his mother. She was a plain and pragmatic woman, from a family of mill-workers, growing up during the Ulster industrial revolution.
Some singer-songwriters are innate storytellers. Their songs encompass the sum total of their experiences and the world they live in. This is why, even though such a song may simply be a few moments of personal reflection, it is so much more than an act of introspection or a historical time capsule. And, beyond the emerging science of song and power of music, its timelessness and universality are both due to how the singer-songwriter conveys those few moments of reflection through his / her song performance — so that it is fresh each time and evokes some of those very moments in real-time the listeners. In this sense, Joni Mitchell has always been in a class of her own.
The condition is known as achromatopsia, where Harbisson's entire world was just black and white. Till he got an eyeborg permanently attached to his body. Brave man. Now, he can identify colors by their musical tones, even discerning them beyond normal visual range. It wasn't an easy road either, given how he had to learn all the various sounds, associate them with the appropriate colors and manage people's responses and reactions to him as he went about his daily world.