Photo chemical smog always contains

Detailed Solution:

The correct answer is “Ozone”.

The photochemical smog always contains the Ozone gas or O3 as a pollutant.

Photochemical smog is a type of smog that is produced when UV light originating from the sun interacts with the oxides of nitrogen present in the atmosphere.

This type of smog usually manifests as a brown haze and is most commonly seen in highly populated cities that are placed in relatively warm climates.