countable/uncountable in different situations.
Examples

"Pollution" is uncountable noun.

much pollution (X)
It's too much pollution in the country. (O)
There isn't much pollution in the area. (O)
A lot of pollution. (O)

Why the situation that add "too" before "much" is use to be with "pollution"?
And why that can be use in negative sentences?(much pollution)

Question

countable/uncountable in different situations.
Examples

"Pollution" is uncountable noun.

much pollution (X)
It's too much pollution in the country.  (O)
There isn't much pollution in the area. (O)
A lot of pollution. (O)

Why the situation that add "too" before "much" is use to be with "pollution"?
And why that can be use in negative sentences?(much pollution)

Answer

The following are all correct:

There is much air pollution in Beijing.

There's a great deal of air pollution in Beijing. ("A great deal" is better English than "a lot of", although "a lot of" is very common.)

There's too much air pollution in Beijing. (There's more air pollution than is safe for people.)

There isn't much air pollution on Vancouver Island.

There isn't too much air pollution on Vancouver Island. (Here, "there isn't too much" is the same as "there isn't very much". Both are the same as saying "There isn't much air pollution on Vancouver Island.)