Tax Exemptions for Charities: A Grey Area?

Kyaa karta hai? I'm trying to wrap my head around tax exemptions for charities in India. According to Section 12A of the Income Tax Act, 1961, a charitable trust is exempt from income tax if it's registered under Section 12AA. But what if the trust is involved in some commercial activities? Does it suddenly lose its exemption? And what if it's not even registered but still doing charitable work? Does the IT department consider it for exemption under Section 11? Kyaa logon ke khatre mein jaata hai? I'm so confused.