Some gases are responsible for the heating of the atmosphere (greenhouse effect). Identify from the following the gaseous species which does not cause it.

Which air pollutant is responsible for the Bhopal gas tragedy?

Photochemical smog consists of an excessive amount of $X$ in addition to aldehydes,ketones,$PAN$,etc. $X$ is:

Identify the correct statements from the following:
$I$. Photochemical smog has high concentration of oxidising agents
$II$. $NO_2$ is present in classical smog
$III$. Higher concentration of $SO_2$ in air can cause stiffness of flower buds
$IV$. pH of rain water is approximately $7.5$

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

List-$I$ Industry	List-$II$ Waste Generated
$A$. Steel plants	$I$. Gypsum
$B$. Thermal power plants	$II$. Fly ash
$C$. Fertilizer industries	$III$. Slag
$D$. Paper mills	$IV$. Bio-degradable Wastes

Choose the correct answer from the options given below:

Which of the following is not a common component of photochemical smog?