Which of the following gases is not a greenhouse gas?

Excess of which of the following in water causes blue baby syndrome disease?

Given below are two statements.
Statement $I$: The non-biodegradable fly ash and slag from the steel industry can be used by the cement industry.
Statement $II$: The fuel obtained from plastic waste is lead-free.
In the light of the above statements,choose the most appropriate answer from the options given below:

What kind of steps should be taken to control environmental pollution?

Which of the following are the greenhouse gases?
$A.$ Water vapour; $B.$ Ozone; $C.$ $I_2$; $D.$ Molecular hydrogen
Choose the most appropriate answer from the options given.

State the name of components of photochemical smog and mention two solutions to control photochemical smog.