I know many people are critical of Ramachandra Guha’s India After Gandhi: The History of the World’s Largest Democracy (e.g., my friend Reihan Salam is not a big fan), but Amazon is running a Kindle Deal on it (at least in the USA). So it’s $1.99 currently.
The original book was published in the 2000s, but this is a “revised and updated” version. So I assume it has a bit more on the last 20 years. Whatever you think about it, it is probably worth reading at some point.