According to the $2001$ census,the population growth rate was approximately: (in $;\%$)

What are the probable factors that contributed to the population explosion in India?

The population growth of India from $1981$ to $1991$ is (in $\%$)

Population explosion occurs due to

On which day did the world population reach the $5^{th}$ billion mark?

The world population in $1900$ was ........ billion,which increased rapidly to ........ billion in $2000$ and reached ........ billion in $2011$.