Polar stratospheric clouds facilitate the formation of .... .
$CIONO _{2}$
$HOCl$
$ClO$
$CH _{4}$
Give the details of different layer of atmosphere and briefly describe about the substance in it.
Write name of the pollutant found in Troposphere.
What are the major causes of water pollution? Explain.
What do you mean by Biochemical Oxygen Demand $(BOD)$ ?
Fill in the Blanks :
$(1)$ The substance that spreading pollution is called .......
$(2)$ The fullform $DDT$ is .......
$(3)$ The area of $10\, km$ to $50\, km$ from the sea level is called .........
$(4)$ Harmful ultraviolet sun radiation come to the earth is blocked by .....