A man is seen trapped amid the debris of an under-construction flyover after it collapsed in Kolkata, India, March 31, 2016. Using saws, small cranes and bare hands, rescuers on Friday cleared the crumbled concrete and twisted steel from an overpass that collapsed onto a crowded Kolkata neighborhood, killing at least 23 people and injuring more than 80. With more than half the debris cleared by Friday morning, 67 people have been pulled out alive, police said. (Photo by Rupak De Chowdhuri/Reuters)

A farmer harvests broccoli in the town of al-Ansariyeh south of Sidon, Lebanon March 15, 2016. (Photo by Ali Hashisho/Reuters)

People walk during a polluted day in Shenyang, Liaoning province, March 31, 2016. (Photo by Reuters/Stringer)

Police in riot gear hold back demonstrators against U.S. Republican presidential candidate Donald Trump outside the Hyatt hotel where Trump is set to speak at the California GOP convention in Burlingame, California, U.S., April 29, 2016. (Photo by Noah Berger/Reuters)

A terrace of a house is covered with ash after the eruption of the Fuego volcano at San Miguel Los Lotes in Escuintla, Guatemala, June 6, 2018. (Photo by Carlos Jasso/Reuters)

Afghan children play on the remains of a Soviet-era armored personnel carrier on the outskirts of Jalalabad on February 15, 2016. Soviet troops withdrew from Afghanistan on February 15, 1989, after ten years of fighting against Mujahidin militiamen. (Photo by Noorullah Shirzada/AFP Photo)

A girl uses a mattress as a raft during the flood after the Xepian-Xe Nam Noy hydropower dam collapsed in Attapeu province, Laos July 26, 2018. At least 26 people were killed and over 3,000 people stranded after a hydroelectric dam built collapsed in southeastern Laos, destroying thousands of homes and leaving an unknown number of dead. (Photo by Soe Zeya Tun/Reuters)

Aerial view of a boat working in the green water of Taihu Lake covered by blue-green algae, Wuxi city, Jiangsu province, China on May 23, 2018. (Photo by Imaginechina/Rex Features/Shutterstock)