Like it or not, but Telegram is a pain for the government
This ban is being done to show the government agencies are not incompetent

Likely, they knew that the NEET question papers would again get leaked and would be shared on Telegram. Another leak will actually dent the government's reputation. China, a few days back, showed the world that it can host the world toughfest exam (that decides students' career path) without any glitch or leak. India's aspiration is to become stronger than China, but we are 100 years behind them.