The atmosphere of city is very mush polluted (you don't need both 'very' and 'much' - very suffices)

I don't want to do exercise outside today this morning due to/because of the terrible atmosphere is so terrible.The weather news reports that the  PM2.5 of the atmosphere is way over the standard. The index is even is up to the highest degree/level. Doctors warn people not to go out if possible. The polluted air is like poison/toxic gas. How to find out a proper way to clean up the polluted matter, or reduce/cut down on it? We should stop falling out/arguing/disagreeing with anyone at involved in environment protection. I hope to have a breath of fresh air every day.

error better notes

The atmosphere of city is very mush polluted.   You would not ever say "much polluted".

Alternatives are:- really polluted, extremely polluted.

I don't want to do exercise outside today this morning due to the atmosphere is being so terrible.

The weather news report PM2.5 of the atmosphere is over the standard.

The weather report says the pollution index is at PM2.5, which is over the [safe] standard.

The index even is up to the highest degree. [The index is the highest it has ever been.]

Doctors warn people not to go out if possible.The polluted air like poison gas. How to [can we] find out a proper way to clean up the polluted matter? or cut down on it? We should stop falling out with anyone at environment protection. I hope to have a breath of fresh air every day.