Trying to route a small BGA Device

The clearance around the green track overlaps with the copper of pads D3 and D4, so that is a clearance violation.

That is probably set in the footprint properties, or the pad properties. In that case, this clearance override only applies to the pads, and not to the tracks. You also have to adjust the clearance for the nets themselves. Either with the normal methods such as net classes, or write a custom rule that only applies for this footprint. You can do this with intersectsCourtyard()

Also, this would need 100um tracks and 100um clearance. Have you verified your PCB manufacturer can make this?