Mount Isa ( EYE-zə) is a city in the Gulf Country region of Queensland, Australia. It came into existence because of the vast mineral deposits found in the area. Mount Isa Mines (MIM) is one of the most productive single mines in world history, based on combined production of lead, silver, copper and zinc.With an estimated urban population of 18,588 as of June 2018, Mount Isa is the administrative, commercial and industrial centre for the state's vast north-western region. Population has decreased moderately at an average annual rate of -2.66% year-on-year over the five years to 2018. Although situated in an arid area, the artificial Lake Moondarra 19 kilometres (12 mi) north of the city on the Leichhardt River provides both drinking water and an area for watersports, birdwatching and recreation. Locals often refer to Mount Isa as "The Isa".Due to the lead production in the city, Mount Isa has one of the most intensive air quality monitoring systems in Australia. Concerns have been raised over childhood lead contamination and air pollution within the city. The Mount Isa Mines (MIM) in particular are a source of significant lead pollution.