Harassment at workplace

I am working as a doctor in the government hospital here. There is a senior college of mine (who is of the same cadre as me but given additional charges) who has been harassing me aince last 1 1/2 years. Initially I ignored but now he keeps doing it intentionally. It's in the form of little petty things like not giving leaves, deliberately changing duties on dates that don't suit me, putting duties on the dates am on officially leave, arguing with me and talking in a demeaning way in front of others. Once he even asked me to get out of the room in front of other doctors. I have written several times to higher officials regarding the same and they have been warning him verbally many a times but his behaviour doesn't change. He s the son in law of a local MAL due to which no one takes an official action against him. I am feeling more and more mentally exhausted by him and don't know what to do next. Being a female, I am not supported by other male colleagues too since he gives special favours to his favourites. Kindly guide me as to how can I threaten him to stop this. Is there any law for protection of women from mental harassment at workplace?