in Qayyarah, about 31 miles (50 km) south of Mosul, Iraq, Sunday, October 23, 2016.in Qayyarah, some 50 kilometers south of Mosul, Iraq, Sunday, Oct. 23, 2016. Islamic State fighters torched a sulfur plant south of Mosul, sending a cloud of toxic fumes into the air that mingled with oil wells the militants had lit on fire to create a smoke screen. (Photo by Marko Drobnjakovic/AP Photo)

A boy looks on as fire fighters try to extinguish the fire at oil wells, were set on fire by Daesh terrorists as they fled after Al Qayyarah town's cleansing from Daesh militants as the operation to retake Iraq's Mosul from Daesh continues, in Al Qayyarah Town of Mosul, Nineveh, Iraq on November 02, 2016. (Photo by Yunus Keles/Anadolu Agency/Getty Images)

Labourers pour molten iron into a container at a foundry in Xiangfan, Hubei province in this July 2, 2010 file photo. Iron ore is enjoying its biggest rally in years, outpacing copper and oil so far in 2016, but still weak forward prices show it may be tough to stretch the bullish outlook. Improving steel prices in top market China are helping fuel iron ore's climb as producers gear up for a seasonal uptick in demand. Yet there is no shortage of doubters who see gains in the bulk commodity as fleeting given a large glut and challenges for China's economy. (Photo by Reuters/Stringer)

Nepalese Hindu devotees offer oil lamps in the Bagmati River as they observe the festival of Bala Chaturdashi in the early morning hours at the Pashupati Temple in Kathmandu, Nepal, 28 November 2016. Seven kinds of seeds – paddy, barley, sesame, wheat, gram, maize and finger millet – are sown around the temple premises in the name of loved ones departed during the last three years, in the belief that the departed souls will receive salvation. (Photo by Narendra Shrestha)

A soup for the students is pictured during an activity for the end of the school year at the Padre Jose Maria Velaz school in Caracas, Venezuela July 12, 2016. Due to the faltering socialist economy and the plunge in global oil prices, Venezuela has been in recession since early 2014. Due to the faltering socialist economy and the plunge in global oil prices, Venezuela has been in recession since early 2014. It suffers from the world's highest inflation and is experiencing shortages of basic goods, from milk to medicines. (Photo by Carlos Jasso/Reuters)

The Chilean ship “Skorpios II” is seen after it ran aground in “Maillen” island, near Puerto Montt, south of Santiago, in this handout picture from the Chilean Navy, February 5, 2015. According to the Chilean Navy, the ship's 89 passengers and 31 crew members were all evacuated and no oil spills or casualties were reported. (Photo by Reuters/Chilean Navy)

A boy crawls under a cow during a religious ceremony celebrating the Tihar festival, also called Diwali, in Kathmandu, October 23, 2014. Hindus all over Nepal are celebrating the festival during which they worship cows, which are considered a maternal figure, and other animals. Also known as the festival of lights, devotees worship the goddess of wealth Laxmi by illuminating and decorating their homes using garlands, oil lamps, candles and colourful light bulbs. (Photo by Navesh Chitrakar/Reuters)

Tao Xiangli gets out of his homemade submarine after operating it in a lake on the outskirts of Beijing September 3, 2009. Amateur inventor Tao, 34, made a fully functional submarine, which has a periscope, depth control tanks, electric motors, manometer, and two propellers, from old oil barrels and tools which he bought at a second-hand market. He took 2 years to invent and test the submarine which costs 30,000 yuan ($4,385). (Photo by Christina Hu/Reuters)