Which of the following is/are the characteristic/characteristics of Indian coal?

Answer: (a) 1 and 2 only

High ash ✓ and low sulphur ✓.

Statement by statement

1. ✓ CORRECT Gondwana coal formed from plant matter that drifted in with sediment, so it carries 30–45% ash.

2. ✓ CORRECT Usually under about 1% sulphur — lower than much imported coal.

3. ✗ WRONG — it is HIGH Indian coal ash has a high fusion temperature, so it does not melt easily into slag inside boilers.

The idea

Coal quality has several separate measures. Ash is the mineral residue left after burning; sulphur affects emissions, while ash-fusion temperature tells when that residue melts. One poor property does not prove that all the others are poor.

Coal enters the furnace → Combustible matter burns → Mineral ash remains → Further heating may soften the ash → Molten ash can form slag → Boiler design must allow for the ash properties

Why the others are wrong

(b) Drops high ash — the single best-known property of Indian coal (30–45%).

(c) The ash-fusion temperature is high, not low.

(d) Assumes a “poor-quality” coal must melt easily too. Its ash-fusion temperature is high, so its ash doesn’t turn into slag easily.

The trap

Once you know the ash is high, it is tempting to assume every feature is “bad”. The ash-fusion temperature is actually high.

Also know

Coking coal can form the strong coke needed in a blast furnace; thermal coal is mainly burned for heat and electricity. North-eastern Tertiary coal can have more sulphur than the broad Gondwana pattern tested here. Washing can remove some mineral matter but cannot turn every coal into coking coal.