Indian Runner ducks march past farm buildings at the Vergenoegd wine estate near Cape Town, South Africa, May 16, 2016. Each day, a quack squad of killer ducks are released for the first of two sorties at South Africa's Vergenoegd wine farm in Stellenbosch. Their mission – seek and destroy thousands of pests out to ruin the season's harvest. Fanning out across the vineyards, some 1,000 Indian Runner ducks hone in on their hidden targets with uncanny precision, locating the tiny white dune snails feasting on budding vines. (Photo by Mike Hutchings/Reuters)

A rider on horseback competes in the Margalla Festival Tent Pegging Championship in Islamabad, Pakistan, June 5, 2016. Tent pegging is an equestrian sport popular in India and Pakistan, with a history going back to the cavalries of ancient armies. (Photo by Caren Firouz/Reuters)

A homeless girl asks for alms outside a coffee shop in Mumbai, India, June 24, 2016. (Photo by Danish Siddiqui/Reuters)

A dog groomer prepares a model dog during the 2nd Annual Shenzhen International Pet Exhibition, July 14, 2016, in Shenzhen, China. The pet exhibition runs from July 14 - 17, 2016 at the Shenzhen Convention & Exhibition Center. (Photo by VCG/Getty Images)

A man lies in the sea grass at a beach on July 18, 2016 in Qingdao, Shandong Province of China. The enteromorpha prolifera spread on the beaches in Qingdao and were under clearing. (Photo by VCG/VCG via Getty Images)

A woman mourns the loss of her husband, next to a placard which reads “I'm a pusher”, who was shot dead by an unidentified gunman in Manila on July 23, 2016. Philippine President Rodrigo Duterte swept to power in May on a promise to clampdown on drugs, and police have since confirmed killing nearly 200 people in a two-month crime blitz. There has also been a surge in killings by anti-drug vigilantes who leave victims' corpses on city streets wrapped in packaging tape with signs accusing them of being drug dealers. (Photo by Noel Celis/AFP Photo)

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)

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)