A. CO
B. SO2
C. NO2
D. CO2
A. Colloids or aerosols
B. Powder
C. Dust
D. Smoke
A. Ozone and iodine
B. Chlorine or its compounds
C. Ultraviolet light for irradiation of water
D. All A., B. & C.
A. Forest fire
B. Deforestation
C. Volcanic eruption
D. None of these
A. Color
B. Bad taste
C. Foul odour
D. Bacteria
A. Nothing but black smoke
B. A combination of smoke and fog
C. A liquid particle resulting from vapor condensation
D. A solid particle e.g. fly-ash
A. Coal mining
B. Limestone mining
C. Textile
D. Asbestos