Ozone is formed in the upper atmosphere by a photochemical reaction with $O_2$ in the presence of

Match $List-I$ with $List-II$:

$List-I$ (Pollutant)	$List-II$ (Source)
$A$. Microorganisms	$I$. Strip mining
$B$. Plant nutrients	$II$. Domestic sewage
$C$. Toxic heavy metals	$III$. Chemical fertilizer
$D$. Sediment	$IV$. Chemical factory

Choose the correct answer from the options given below:

Fill in the blanks:
$(1)$ Carbon dioxide is found in the ................. layer.
$(2)$ $A$ high concentration of carbon dioxide is responsible for ................. .
$(3)$ ................. gas is used in air conditioners.
$(4)$ Acid rain causes damage to the ................. monument (wonder).

Which gas contributes the least to global warming?

How is electricity produced in a thermal power station?

The pollutants which come directly into the air from sources are called primary pollutants. Primary pollutants are sometimes converted into secondary pollutants. Which of the following belongs to secondary air pollutants?