Question

In Indian metropolitan cities like Delhi, major air pollutant is
A. SPM
B. $\mathop {SO}\nolimits_x$
C. $\mathop {NO}\nolimits_x$
D. $\mathop {CO}\nolimits_{} and\mathop {CO}\nolimits_2$

Answer 1

Hint:- Air pollution is defined as the contamination of air due to presence of undesirable and toxic substances in the environment , usually in air. In almost all the cities including that of Delhi the pollution is reaching the peak of its position. The air pollutant may be oxides of sulphur , oxides of nitrogen and many others.

Complete Answer:- Different kinds of air pollution are present in the environment but their concentrations vary. Some are present in less amount and some are present in huge extent based on the city that is taken into consideration and also the amount of material released the most in that city.
Now let us have a look on given options:-
SPM :- it is also known as suspended particulate matter. In Delhi it is present in 62% of composition in the environment . It has both liquid and gaseous particles suspended . It consists of dust , ash and liquid droplets . It is released from the industries and a large number of factories are settled in Delhi.
$\mathop {SO}\nolimits_x$ :- it is called as oxides of sulphur . It is present as 11% in composition in Delhi environment. It is a kind of primary pollutant and it is released from oil refineries , smelters of ores and combustion of sulphur containing fuels.
$\mathop {NO}\nolimits_x$:- it is called oxides of Nitrogen. It is present as 0% composition in Delhi environment . It is a kind of primary pollutant. It is released from combustion of fossil fuels at high temperature in automobiles engines and this is illegal in Delhi .
$\mathop {CO}\nolimits_{} and\mathop {CO}\nolimits_2$ :- these are known as carbon monoxide and carbon dioxide in the environment . It is present in 27% of composition in Delhi environment. It is a type of primary pollutant. These become pollutant only when their concentration reaches beyond critical value.

Our required option is a SPM.

Note:- Delhi leads the country in its levels of air pollution. It has more cars than states of Gujarat and West Bengal put together. In 1990's Delhi ranked fourth among the 41 most polluted cities of the World. Air pollution problem in Delhi became so serious that a Public Interest Litigation (PIL) was filed in Supreme Court of India