Which of the following factors is responsible for water pollution?

How is biogas produced?

Which one of the following statements regarding photochemical smog is not correct?

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:

Explain tropospheric pollution caused by oxides of nitrogen.

The poisonous gas that is released during the combustion of petrol in a car engine is