Identifying the Doctrine of Plea Bargaining in Indian Constitution

Question from CLAT UG, 2020: "Explain Plea Bargaining and discuss whether it is a viable alternative to the existing system of trial in India."

Honestly, I found this question tricky because most students, including myself, get confused between the concept of Plea Bargaining and the concept of 'Bail'. See Article 21 of our Constitution - it talks about the protection of life and personal liberty. Now, Plea Bargaining is actually recognized in our penal code - Section 321 CrPC. It basically allows a person to plead guilty to a lesser charge in exchange for a reduced sentence. But can we really say it is a viable alternative to the existing system of trial in India?