Sci-Hub has been blocked in India

Depends how it's implemented - once you've found the correct IP address you still have to connect to it, and some ISPs block and otherwise mess with traffic at that stage.

In the early days of the IWF blocklist I had trouble with a Joomla install timing out when using my own ISP but it was fine if I used a proxy. It turned out to be because the Joomla install was on cheap GoDaddy hosting, and something on the IWF list was in the same IP block as my hosting - so my ISP was directing traffic through a filtering proxy which was causing problems with Joomla.

(IP address alone isn't enough to identify a particular site, filtering everything for target websie was too expensive, so IP-based filtering was used to decide which traffic went through the filtering proxy.)

The site seems to be blocked for me in the UK, too, by the way.