Which of the following is harmful to calcium-containing structures and is responsible for causing cough and throat irritation in humans?

$A$ large number of fish are suddenly found floating dead on a lake. There is no evidence of toxic dumping,but you find an abundance of phytoplankton. Suggest a reason for the fish kill.

Which of the following reactions is directly related to the corrosion of the Taj Mahal?

How is the depletion of the ozone layer created in the atmosphere over Antarctica? Explain with reactions.

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

List-$I$	List-$II$
$A$. Nitrogen oxides in air	$I$. Eutrophication
$B$. Methane in air	$II$. $pH$ of rain water becomes $5.6$
$C$. Carbon dioxide	$III$. Global warming
$D$. Phosphate fertilisers in water	$IV$. Acid rain

Choose the correct answer from the options given below:

Which of the following methods can be used to control water pollution?