- I am hearing a lot about the problem of ragging these days.
- I am hearing a lot of the problem of ragging these days.
What ia the difference? Which is correct?
Both statements can be interpreted to mean the same thing, but the second is likely to cause confusion. I would use the first sentence, to make it clear that "about the problem" is a separate prepositional phrase that is modifying the noun phrase "a lot" (which is the object of the verb "hearing").
The phrase "a lot of" is used as a quantifier, and paired with a plural or uncountable noun (e.g. "a lot of chickens are in the yard" or "a lot of water spilled over the dam"). It can also mean "a large percentage of" (e.g. "a lot of the floor is carpeted" or "a lot of people enjoy pizza"). Even if neither of those uses is intended, the second sentence has the potential to cause confusion even to native speakers.