On certain conjectures of Clozel and Shahidi

In this paper, for symplectic and split odd special orthogonal groups Gₙ, we prove the enhanced Shahidi conjecture on generic representations and the Clozel conjecture on unramified representations, for local Arthur packets. These results have interesting global implications, in particular, we confirm a conjecture of Arthur and Clozel on the local components of automorphic representations in the discrete spectrum. As further applications, towards the generalized Ramanujan problem as posted by Sarnak, we show that the Ramanujan conjecture for GLₙ implies a sequence of conjectures of Clozel on local components of automorphic representations of Gₙ.