I never thought we'd have to worry about what was overhead - not in my whole life. Who would even think of poisoning our skies? Letting chemicals rain down on the population - an ever-present threat. This is not that big a planet so it doesn't make sense that anyone would want to destroy it, and destroy it they will, if the rug doesn't get pulled out from under the culprits. Obviously whoever is responsible, doesn't realize that they and their own family would be included in the illness and demise of the population.

I don't know if this is true or not, but do remember reading somewhere about a very early civilization that believed their lives depended on a hidden "God" inside the temple on the hill. This "god" was actually the priest incognito who claimed to have power over all - and he did. He knew how to mix up sedative chemicals in incense to create an overpowering smoke that layered itself over the city every day and night, blocking out the sun and moon so the people would never be able to see outside their little space. The priest figured if they couldn't see anything and didn't know any better, they would never leave the area and he would have plenty of slaves who depended upon the unseen and omnipresent "god" in the temple for their sustenance. He was pretty smug about the power he held over the people.

The priest maintained that power by declaring anyone who noticed or spoke up about the temple pouring smoke vapors every day, anyone who asked about it would be given to the god inside the temple - "heaven, if you will?" via a huge send off ceremony.
Either that or they would have to give up their first born daughter to the interior, or their first born son as a guard of the temple, chained to the doorway. Most families with daughters kept quiet and trained their children to never speak out loud lest someone overhear and report them. They burned their incense (provided by the temple guards) religiously inside their homes just to make sure they were breathing the holy vapors everywhere and all the time.

Once in a while, a child would point to the temple and ask who lived there, and why? If they spoke too loudly, they were next to go and they never returned to their home. That meant the vapors didn't affect them - they must be "holy" and it should be an honor for the family to send them inside the temple where they obviously belonged. The child would serve "god" in the heavenly temple. The parents would receive gifts, they would have prestige over others that their child was "chosen" and the aware child would be out of the way.

Inside the temple, the priest used the girls for his own entertainment. Boys worked. Hard. He had underground tunnels where he could leave any time he wanted to blend in with the population and learn about the people who lived there, collect herbs and roots from suppliers that he would burn inside the temple on his pyre, that went out the chimney and all over the land while he stayed inside where it was clean and safe. Do you see how he could do that and get away with it?

Well, one of the girls who did end up inside the temple for good wasn't as dumb or as drugged as the priest expected. She was alert to his whereabouts and followed him outside one night as he slipped out to visit his suppliers.
People who had no idea this was the hidden priest of the temple.
He returned to find the girl gone from the temple.

He was terrified - she might tell! And tell she did, to everyone who would listen. They were shocked that the girl they thought was "going to heaven" in the temple with god came back to tell them the truth - that the guy was an impostor and no better than anyone else.

The only thing he had that was different, was chemicals and the knowledge to use them on unsuspecting, fearful people. But now they knew what was really going on, and how they were being used and abused. Their fear disappeared. They got together and stormed the temple to expose everything inside. They found very little, but a huge burn pile and a tall chimney where the smoke came out. The priest ran out the back way, and disappeared into the land, never to be seen again.
His power was gone, the fire went out, fresh air returned, and the people woke up.

Ever since that time, when unknown substances floated around in the air above the people and smoke vapors were being poured out from a hidden source, they became suspicious and willing to expose them to the world.
Funny how the actual culprits became fearful and exposed themselves instead.

All the people ever wanted was to breathe fresh air and see the stars again.

That's a timely story!