Which of the following is not a metal present in e-wastes?

What is the full form of $FOAM$?

How many sentences are correct?
$(1)$ $CNG$ burns most efficiently.
$(2)$ $CNG$ cannot be adulterated.
$(3)$ $CNG$ is cheaper than petrol and diesel.
$(4)$ In the $1990$s,Delhi ranked $4$th among the $41$ most polluted cities of the world.

Match the following important dates/events related to environmental legislation in India:
$(i)$ Air (Prevention and Control of Pollution) Act
$(ii)$ Environment (Protection) Act
$(iii)$ Water (Prevention and Control of Pollution) Act $(1974)$

Today,the concentration of greenhouse gases is very high because of:

Estuaries occur in which of the following Indian states?