Which gas is not an air polluter?

The correct answer is Option (2) → Ozone

Air pollution is the addition of harmful gases, dust and smoke to the air. Burning fuels, mining and industries are its main sources.

Option (1) Ammonia — An air polluter. Ammonia is one of the pollutants of air pollution.

Option (2) Ozone — Not an air polluter. The air pollutants are oxides of sulphur and nitrogen, carbon monoxide, hydro-carbon, ammonia, lead, aldehydes, asbestos and beryllium. Ozone is not among them.

Option (3) Carbon monoxide — An air polluter. Carbon monoxide is released by burning fossil fuels and pollutes the air.

Option (4) Hydrocarbon — An air polluter. Hydro-carbons are among the pollutants of air pollution.

Note: The air row of the pollution table names ammonia, carbon monoxide and hydro-carbons, but not ozone. NTA asked about the gas the table leaves out, so know each list fully.