How would I define the words in bold below?

It will improve the environment by reducing pollutions.

How to classify this bolded part of the sentence grammatically?

I understand that it's used for saying how something is done, but I can't find grammar rules related to it in my textbook.

  • 1
    I would classify it as an error.
    – Hot Licks
    Feb 16, 2020 at 3:44
  • 4
    It's a prepositional phrase. Reducing is a gerund, i.e. the present participle of a verb that still functions as a verb within its phrase ("reducing pollution"), but as a noun within the larger context of the entire sentence ("improve by [noun phrase]"). As an aside already mentioned above, pollution is uncountable. You can't have one pollution, two pollutions, three pollutions. There is no such thing as "pollutions". Either there is pollution, singular, or there is no pollution, also singular.
    – ЯegDwight
    Feb 16, 2020 at 4:03

1 Answer 1


It will improve the environment by reducing pollutions.

Pollution is singular. So the above statement would be classified as an error.

As RegDwight already said, pollution can't be plural, it is singular. There is no such thing as "pollutions" as it is uncountable. Thus *pollutions** is incorrect.

If the statement had "pollution", then it would have been classified as a prepositional phrase. But the above statement is an error.

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