Different story from the lede story here maybe. This sounds like careless kite flyers who left pieces of this sharp string behind entangled in tree branches or wires over a roadway, and did not mention anybody actually being accused.
There have been deliberate booby traps heard of in the US where someone strings picture wire over a street. It has maimed and killed motorcycle riders and damaged cars.
I didn't read far enough in the story. I got to the part in the Hindu times story I saw, “A case of negligence has been registered in both incidents and investigation has begun, police said.” I assumed that this meant that this was at least partially intentional. To me it seems somewhat unlikely that string embedded with glass would stay suspended at neck height across roadways in several different locations causing injuries. That seems like more of a freak accident type of situation and not something that all of a sudden causes multiple similar incidents. String embedded with glass has been around for hundreds of years. I remember reading about this sport when I was a kid and even how to make the string. All of a sudden we have many injuries and three fatalities in one day. Maybe a Chinese entrepreneur came out with a stronger sharper variety. But it still seems suspicious to me and possibly connected to social media.