In municipal sewage,$BOD$ values (in $ppm$) are

The chemical entities present in the thermosphere of the atmosphere are

The statements that are $TRUE$:
$A$. Methane leads to both global warming and photochemical smog.
$B$. Methane is generated from paddy fields.
$C$. Methane is a stronger global warming gas than $CO_2$.
$D$. Methane is a part of reducing smog.
Choose the most appropriate answer from the options given below:

Which among the following statements is $NOT$ a principle of green chemistry?

Air pollution that occurs in sunlight is:

The effect of smog is observed on which of the following?