Chroma noise

The Chroma noise in photos shows as random speckles of red, green and blue pixels where they shouldn’t be. It also appears as larger areas of uneven colour in your photo. By default Lightroom has a setting of 25 for Amount. This is actually a spot-on choice for most photos. If anything, it may even be slightly aggressive, but not so much as to warrant worry.

Use Detail to help prevent removal of small areas of colour that are supposed to be there. To remove the larger areas of uneven colour and colour banding, use Smoothness.