Which one of the sentences is correct?
Is it necessary to put 'it'?
1. If you find anyone dropping objects from heights, report to the police.
2. If you find anyone dropping object from heights, report it to the police.
If you merely say "report to the police", then you are indicating that you have to go and make your presence know to the police.
So if you want to report that something is happening, you must report it.