With reference to furnance oil, consider the following statements: ​ 1. It is a product of oil refineries. ​ 2. Some industries use it to generate power. ​ 3. Its use causes sulphur emissions into environment. ​ Which of the statements given above are correct? ​

Furnace oil is a heavy residual fraction left after lighter products like petrol, diesel and kerosene are distilled off in a refinery, so statement 1 is correct. Industries such as cement, steel, glass, ceramics and textiles burn it in furnaces and boilers, and it is used for captive power generation, so statement 2 is correct. Because the crude-derived residue carries sulphur, burning it releases sulphur dioxide and sulphur trioxide, so statement 3 is correct.

Each wrong option drops one correct statement. A leaves out statement 3, B leaves out statement 1, and C leaves out statement 2.

The core idea is the refinery product slate: heavy residues are sold as industrial fuels, and their sulphur content drives air pollution. For Mains (GS-III, environment), this links to fuel quality norms, the push to shift industry from furnace oil to natural gas, and sulphur limits in fuels. Note that the policy shift away from furnace oil is a recent development, so describe it as a trend rather than a settled rule.

Trap: Aspirants often assume furnace oil is not a refinery product or that only transport fuels cause sulphur emissions, and so mark option A or C.