Harassment at the public places in a deliberate attempt terrorise

I have been facing terrorism in the form of harassment, threats and all kinds of methods described in the criminal group stalking described in Wikipedia from a group of persons which has a wide network of volunteers all India wide and on a 24/7 basis. All these activities started ever since I left an institution in which I had been working though initially I wasn't aware of this.Their idea is to harrass me and humiliate me wherever I am as well as slander me in order to disrepute me among the immediate vicinity of my residence as well as at my public places.The masterminds of this heinous criminal activities are neither strangers nor ordinary locals but those who were working with me in that institution about which I mentioned earlier. They want vent their hatred and animosity towards me through these ignoble and mean activities. I know that in order to subject me these kind of humiliation on a 24/7 basis they have to keep a high alert on me which is criminal offence.I saw many people who observe me in very secretly whenever I start a journey and inform their links to keep a watch over me on all my movements. I would like to go legal way to stop these activities but before that I would like to know what advice you can offer to find a solution to such a vexing problem.