Smog is also caused by large amounts of coal burning, which creates a mixture of smoke and sulfur dioxide. World coal consumption was about 6,743,786,000 short tons in 2006[53] and is expected to increase 48% to 9.98 billion short tons by 2030.[54] China produced 2.38 billion tons in 2006. India produced about 447.3 million tons in 2006.