Objectively Speaking, who was the worst Prime Minister in Indian history?

We are not going to Include Modi, as he has (as of posting this) four years left, which can completely change his rankings and how he's remembered.

But every other previous Prime Minister is on the table.

We will be judging by overall popularity, quality of life in India during their reign, how they handled wars (if their leadership was under any), and the Human Development index (HDI) and similar statistics.

Also explain why they were so bad.

(edits: Grammar and the rules)