Hi - I am a little surprised by your question! Not sure what you mean by safe. If you are asking from the perspective of legal issues etc. then RERA will protect you to some extent. I am not sure whether the act too is 100% foolproof, so maybe an additional check by a good lawyer will help.
Otherwise, to the best of my knowledge Pune is no better or worse than most Indian cities (yes - there thankfully are no builders like Amrapali or Supertech). Projects get delivered after some delays; RERA is expected to improve the situation somewhat.
But short answer to your question - it is safe to buy; just do not set unrealistic expectations on appreciation of value.