Thanks for the questions @Shiv_Katira — clarifying them point-wise below.
1. What is the meaning of long term here?
For SGBs, long term means holding for more than 24 months; up to 24 months is short term.
2. What are the applicable tax rates for short-term capital gains?
Short-term capital gains on SGBs are taxed at normal slab rates.
3. What are the applicable tax rates for long-term capital gains? Any ₹1.25L exemption?
If taxable, long-term capital gains on SGBs are taxed at 12.5% (without indexation).
The ₹1.25 lakh LTCG exemption does not apply to SGBs.
4. What is the STCG/LTCG structure for Gold MF / ETF?
Same as gold and SGB: STCG up to 24 months (slab rate) and LTCG beyond 24 months (12.5%), with no ₹1.25L exemption.