The title gives the poem a small joke and a small ache. "Noise cancelling" sounds like headphones, but nothing here is cancelled. The morning din, whatever mix of sounds fills the early hours, is the speaker's only company, and the poem calls it "lean," meaning thin and not very nourishing. It's noise, but it doesn't make anyone feel less alone.
The second stanza turns to the mist, which has "gone / too far / to change things." The line breaks make the mist feel like it is drifting out of reach as you read. Mist usually softens a landscape and hushes it, so its absence suggests the speaker has lost a kind of cover or calm. Now the day is plainly here, and nothing about it feels different.
The mood is quiet, wistful and a little flat. The speaker doesn't complain. They simply notice, and that restraint makes the loneliness feel more real. The poem leaves us with a sense of something missed, just out of reach.