Environment

a mixture of smoke, gases, and chemicals, especially in cities, that makes the atmosphere difficult to breathe and harmful for health

a large amount of water covering an area that is usually dry

change from solid to liquid (e.g. from ice to water)

things that make water, air, and the ground unclean

waste material or things that are no longer wanted or needed

official rules that say what people are allowed and not allowed to do

small pieces of rubbish that have been left lying on the ground in public places

material that people throw away

the process of collecting and changing old paper, glass, plastic, etc. so that it can be used again

not existing any more