In Maharashtra,a $24$ hours toll-free helpline number $1926$ has been set up to provide information regarding:

Select the correct statement regarding conventional chemical farming methods.

The average concentration of $CO_2$ in the atmosphere is

Which act was enacted by the Government of India to protect and improve the quality of our environment and to control environmental pollution?

Select the correct year associated with the Chipko Movement.

Consider the following reasons for the massive fish mortality observed in a lake near a village within a few days:
$(1)$ Excessive use of urea and phosphate fertilizers in nearby crops.
$(2)$ Spraying of $DDT$ using aircraft.
$(3)$ The lake water turned green and foul-smelling.
$(4)$ Initial decrease in phytoplankton in the lake leads to a maximum decrease in photosynthesis.
Which of the above reasons are responsible for the massive fish mortality?