Aircraft report how sure they are of their GPS position. Where many report a poor fix, something is jamming or spoofing it. From gpsjam.org, a day behind.
A cell (~45 km) is jammed when over 10% of its aircraft had a poor fix, with at least 4 to go on. A region's figure is the share jammed of the part in view.
No aircraft, no data: Ukraine has few flights and the Red Sea few receivers, so their figures understate it. Outlined cells are usually busy but went silent, from a closure or receivers going down.