2) There is no equivalent of 911 in India. You can call the police but they usually don't have ambulances. Most cases you will have to take the injured in a private vehicle to the hospital.
3) Harassment by police is a real thing in many places. They will suspect you of being involved in the accident. At least in my state (Kerala) there has been conscious effort to resolve this and seems to be working.
4) There is government hospitals who will treat you, no questions asked. But these are not present everywhere, and many don't have adequate resources (Operation theaters, Intensive Care Units etc) in many of these. So there is a chance that you will have to travel to bigger hospital to get appropriate care.
Anecdote. Few years back , I was driving to my home when police flagged me down and asked me to take a lady injured (she was pillion-riding on a two wheeler) to the hospital. Took then to fairly large government hospital (which is also a medical college). The attending doctor asked me whether I was involved in the accident and the told me I can leave. I informed the relatives of the injured (got numbers from her companion) and left.