Please help

I always wonder what kind of power an ias officer has in district suppose something illegal is going on in district and me as an dm dont want it to happen can i stop it ir suppose some sone kind of illegal project mp mla want to do in my district and i do not approve can he continue it and what kind of things need approval from dm and suppose i do not approve can they still continue by taking approval from my seniors and also if i want something to do in my district do i have the authority to do it i just want to know is there things in district which need my approval which cannot continue without it