This flag reminds some of Pakistan - should it be banned?

NEW DELHI: The Supreme Court is hearing a plea, by the Shia Waqf Board chairman, that seeks a ban on hoisting of green flags with crescent and star at buildings and religious places across the country. The petitioner is alleging that the flag is not religious, and resembles that of Pakistani political party Muslim League.
The petition alleges that the flag had never been part of any Islamic practice, and people should not be allowed to hoist the Pakistani flag in the country.

Usage of crescent and star as symbols, however, predates Pakistan. The crescent was used by Byzantine Empire, for instance. Crescent and star became associated with Islam after it was adopted by the Ottoman Empire. Ottoman Empire was then rivalled by the Safavid Empire, a Shia theocracy based in what is now Iran.
While displaying of a flag, by itself, may not be an offence, if authorities suspect that it indicates support of a banned organisation or may cause a law and order problem, they may act against you.
When an ISIS flag—a black flag with white lettering—was hoisted in Srinagar in 2014, police had registered an FIR under section 13 of the Unlawful Activities (Prevention) Act, 1967, which mentions imprisonment for up to 5 years. ISIS was banned under the same Act in 2015.