Before conrona I remember driving back through France overnight and watching a beautiful sun rise only for it to be met with obvious crossed pattern spraying in the sky only where the sun was rising. No where else on such a sunny morning. I wish I had stopped at the time and taken a video of it.
No clouds in the sky except for where the sun was rising and they weren't clouds..
When conrona started here the planes were grounded for a while because people couldn't travel and the sky was a stunning deep blue colour for ages. It's amazing how nature repairs itself from the damage a small handful of parasites do to it..