1
the cutting down of trees in a large area, or the destruction of forests by people
2
damage caused to water, air, etc. by harmful substances or waste
3
the process of making something dirty or poisonous, or the state of containing unwanted or dangerous substances
4
dry dirt in the form of powder that covers surfaces inside a building, or very small dry pieces of soil, sand, or other substances
5
(of land) the quality of producing a large number of good quality crops
6
not now existing
7
the protection of plants and animals, natural areas, especially from the damaging effects of human activity
8
the fact of soil, stone, etc. being gradually damaged and removed by the waves, rain, or wind
9
waste matter such as water or human urine or solid waste
10
the act of sending out gas, heat, light, etc.
11
a result of a particular action or situation, often one that is bad or not convenient
12
able to decay naturally and in a way that is not harmful
13
the act of getting rid of something, especially by throwing it away
14
something that is likely to cause harm
15
the natural environment in which an animal or plant usually lives
