Speech of opposition : They say that smoking is Mobah (optional)
What is said in Islam : The rules that made for smoking came from Quiaas. Imaam-Mujtahid found the rules about smoking comparing with onion-garlic. Because there is bad odour.It is Maqruh tanjihi to eat unripe onion-garlic. As the smell of smoking in much more than onion and garlic, so that is Maqruh Tahrimi. Overall smoking is injurious to health in many ways.