In mainland China the API was replaced by an updated Air Quality Index in early 2012 and on 30 December 2013 Hong Kong moved to a health based index .
It was formerly used in mainland China and Hong Kong .
In China China the API was replaced by an updated Air Quality Index in early 2012 and on 30 December 2013 Hong Kong moved to a health based index .
It was formerly used in mainland China and Hong Kong .