This will be centered on a Sanjay Gandhi premiership either in 1976 or 1984, so take your pick. I promise both will be interesting in the Chinese sense and a happy ending is rather unlikely, though enleadenment is not guaranteed either.
Black Prince: Sanjay exercises better piloting judgment on 06/23/80. When his mother is assassinated on schedule, he becomes PM. One important thing to keep in mind is his political idol: Ferdinand Marcos. That alone gives you a good idea of where things will go.
The Leader's Right, the Future's Bright: Indira Gandhi holds the federal election scheduled for February 1976 on schedule rather than delaying it. At that point the Emergency was still widely accepted and she'd have retained her 2-1 majority from 1971. Unfortunately socialist radicals have other plans, and in 1977 Sanjay becomes PM while the Emergency is still in place. Free-marketeers will be just as thrilled as they were under Rajiv IOTL, but civil libertarians will not, if they're still alive that is. As a side note, the title is an actual propaganda slogan from the Emergency.
*Important note: Sanjay and Rajiv had a very chilly, if civil relationship IOTL. Rajiv blamed Sanjay for the excesses of the Emergency (which he opposed most of) and his mother's defeat in '77 and subsequent show trials of both Sanjay and Indira. In that he was right: it was Sanjay, as always the decisive voice, who convinced his mother to delay the election and didn't want it held in 1977 either, or probably anytime for that matter.
January 1980, when Indira was swept back to power for a third term and Sanjay was elected the freshman MP for Amethi, which Rajiv would hold throughout his career after his election in a July 1981 by-election.
Family dinner at the PM's residence, 06/11/80. From L-R: Rajiv, Indira, Sonia, Sanjay.