21.
Removal of carbon particles from air involves the principle of

22.
Physico-chemical characteristics of water in water sources undergo changes due to

23.
Sulphur dioxide present in the industrial chimney exhaust causes

24.
Coating of solid waste with impervious material is known as

25.
Taj Mahal is greatly affected due to :

26.
High concentration hydrocarbon pollutants in atmospheric air causes

27.
Which one is not a primary greenhouse gases in the Earth's atmosphere?

29.
Sullage water is –

30.
The gas liberated in the Bhopal gas tragedy was: