I have studied somewhere that smoking is haram but people who use to smoke say it not haram it makrooh.
I want to know is it haram (like alcohol) or it just makroo?
Can anyone give me proper evidence on this matter?
The body which we are using isn't our own property, it is what Allah has given us to use and live in the world and Allah will take it back once we will die. Allah has forbidden harming yourself and this is the reason why suicide is haram in Islam because it is self-harm.
This ayah tells what I am talking about.
You are talking about smoking so as far as I know, smoking cause mouth cancer and it is same as self-harm so it isn't better for you to smoke.
In addition to being destruction, as said in other answer, there are other reasons:
What is haram? If anything that is prohibited by Allah in Quran is haram than it is haram.