International Ozone day is celebrated on- |
|||
(a) |
16th September |
(b) |
7th December |
(c) |
21st March |
(d) |
22nd April |
International Ozone day is celebrated on- |
|||
(a) |
16th September |
(b) |
7th December |
(c) |
21st March |
(d) |
22nd April |