Which is the cleanest country in the world?

Could you elaborate on your question about which country is considered the cleanest in the world? Are you referring to environmental cleanliness, such as air and water quality, or perhaps cleanliness in terms of public health and sanitation practices? Each metric has its own set of criteria and rankings, so a clear understanding of your focus would help provide a more accurate response. Could you please specify which aspect of cleanliness you're most interested in?