Here are some relevant IPC sections that can be used to address online abuse:
a) Defamation (IPC Section 499 and 500),
b) Criminal Intimidation (IPC Section 506),
c) Obscene and Offensive Content (IPC Section 292 and 294),
d) Stalking (IPC Section 354D),
e) Sending Offensive or Annoying Messages (IPC Section 66A - Repealed),
f) Privacy Violation (IPC Section 66E), and
g) Impersonation (IPC Section 416).