World Environment Day is celebrated on

Which of the following is of more immediate concern regarding the carbon cycle?

Jhum cultivation:
$I.$ Also called as slash and burn agriculture,is the farming practice in North Eastern states of India.
$II.$ Farmers cut down the trees of forest and burn the plant remains.
$III.$ The ash is used as a fertilizer and the land is then used for farming or cattle grazing.
$IV.$ After cultivation,the land is left for several years,so as to allow its recovery.
Which of the statements given above are correct about Jhum cultivation?

What human activities are responsible for the increase in the amount of $CO_2$ in the atmosphere?

$1981 =$ Air Act in India :: $1980 =$ ......

Which of the following pollutants are inevitably associated with the existence of man?