The pollution due to oxides of sulphur gets enhanced due to the presence of:
$(a)$ particulate matter
$(b)$ ozone
$(c)$ hydrocarbons
$(d)$ hydrogen peroxide
Choose the most appropriate answer from the options given below:

Classical smog is a mixture of .....

Among the following compounds,which one is not primarily responsible for the depletion of the ozone layer in the stratosphere?

Given below are two statements:
Statement $I:$ Classical smog occurs in cool humid climate. It is a reducing mixture of smoke,fog and sulphur dioxide.
Statement $II:$ Photochemical smog has components,ozone,nitric oxide,acrolein,formaldehyde,$PAN$ etc.
In the light of above statements,choose the most appropriate answer from the options given below:

Which of the following conditions in drinking water causes methemoglobinemia?

The greenhouse effect is caused by ...... .