Fill in the blank with suitable adverb:

_____ there has been a lot of noise pollution.

lately

The correct answer is Option (4) → lately

So, the sentence should read: "Lately there has been a lot of noise pollution."

Explanation:
- "Lately" means recently or in the recent past.
- In the given sentence, "lately" indicates that there has been a significant amount of noise pollution in the recent past.
- This adverb fits well in the sentence to convey the timing of the noise pollution.