unpolluted
US /ˌʌn.pəˈluː.t̬ɪd/
UK /ˌʌn.pəˈluː.t̬ɪd/
1.
không bị ô nhiễm
not affected by pollution (= damage caused to water, air, etc. by harmful substances or waste):
:
•
In areas with unpolluted air, tree branches are often covered with grey, brown and green lichen.