Besides, the question of obviousness or inventiveness has to be judged from the point of view of a man skilled in the art which requires evidence of experts.
This question can be resolved only in opposition or revocation proceedings. But many patents are granted unopposed.
The Act therefore does not guarantee the validity of the patent which can finally be decided only by the High Court in infringement revocation proceedings. There is no system of patents in existence which guarantees absolutely the validity of a patent when granted.
There are many patents which are invalid but the patentee ha some advantage in retaining them. The existence of such patents causes competitors either to buy such patents or obtain licenses from the owner for working them.
Due to the enormous development of technology all over the world which makes it impossible to make a thorough search for novelty and obviousness before grant of a patent.