Which of the following strategies is not useful for mitigating global warming?

Identify the correctly matched pair.

World Environment Day is celebrated on

Which is the main causative factor of desertification?

The $Chipko$ movement was started for the protection of .........

In a pond near a village,a large number of fish suddenly die. Which of the following could be the reason for this?
$(a)$ Large amounts of urea and phosphate are used as fertilizers in nearby fields.
$(b)$ $DDT$ was sprayed in the entire area.
$(c)$ The pond water has become green and dirty.
$(d)$ The population of phytoplankton in the pond has decreased,reducing the photosynthetic capacity.
Which two of the above reasons are responsible?