Section 66A(b) has three main elements: (1) that the communication be known to be false; (2) that it be for the purpose of causing annoyance, inconvenience, danger, obstruction, insult, injury, criminal intimidation, enmity, hatred or ill will; (3) that it be communicated persistently. The main problem here is, of course, (2). "Annoyance" and "inconvenience", "insult", "ill will" and "hatred" are very different from "injury", "danger", and "criminal intimidation". That a lawmaker could feel that punishment for purposes this disparate belonged together in a single clause is quite astounding and without parallel (except in the rest of the IT Act). That's akin to having a single provision providing equal punishment for calling someone a moron ("insult") and threatening to kill someone ("criminal intimidation"). While persistent false communications for the purpose of annoying, insulting, inconveniencing, or causing ill will should not be criminalised (if need be, having it as a civil offence would more than suffice), doing so for the purpose of causing danger or criminal intimidation should. However, the question arises whether you need a separate provision in the IT Act for that. Criminal intimidation is already covered by ss. 503 and 506 of the IPC. Similarly, different kinds of causing danger are taken care of in ss.188, 268, 283, 285, 289, and other provisions. Similarly with the other "purposes" listed there, if, for instance, a provision is needed to penalise hoax bomb threats, then the provision clearly should not be mentioning words like "annoyance", and should not be made "persistent". (At any rate, s. 505(1) of the IPC suffices for hoax bomb threats, so you don't need a separate provision in the IT Act).