Given, \[S{O_2}\] and \[N{O_2}\] causes pollution by increasing?
A.Neutrality
B.Acidity
C.Buffer action
D.Alkalinity

Hint: \[S{O_2}\] and \[N{O_2}\] are the one of the major sources of pollution in the environment and water, especially acid rain. They reach the atmosphere through various human activities like coal burning, fuel production etc. also through some natural processes too, \[S{O_2}\] and \[N{O_2}\] reaches the atmosphere like volcanic eruptions.

Complete answer:
\[S{O_2}\] and \[N{O_2}\] are the oxides of the Sulphur and Nitrogen respectively.
Now let’s have a look at how these hazardous sulphur dioxide and nitrogen dioxide causes pollution in the environment and water.
So both \[S{O_2}\] and \[N{O_2}\] reach the atmosphere and are transported or dispersed here and there through water and through the air currents.
These both \[S{O_2}\] and \[N{O_2}\] react with the water, oxygen and other chemicals that are present in air to produce ‘sulphuric acid and Nitric acid’.
These both acids are hazardous in nature and to human health.
These acids then combine with air and water before falling to the ground and forming ‘acid rain’.
Then, on land and in water they increase the acidity of the water and make it unsuitable for consumption and also to the animals too.
So, from the above discussion we know that the \[S{O_2}\] and \[N{O_2}\] increases the acidity, so they act by increasing acidity.

Therefore the correct option is B. i.e. \[S{O_2}\] And \[N{O_2}\] causes pollution by increasing acidity.

Note:
Sulphur dioxide is a hazardous chemical and irritant. It is known to cause various diseases in humans like asthma. A lot of work has gone into 'scrubbers' for coal-fired power stations, which remove harmful emissions including SO2. These power stations are now truly 'clean coal'.