"Sorry, something went wrong. We're working on it and we'll get it fixed as soon as we can," a message on the Facebook website said.
Several users have taken to Twitter to report the outage around 9 PM Indian Standard Time (IST).
The website downdetector.com, which tracks web services, shows a sharp spike in complaints by users.
All three Facebook-owned properties are market leaders in India in their categories of instant messaging, photo sharing and social networking.