Mahouts return home with their elephants carrying grass to feed them on the eve of the rhino census in Kaziranga National Park in Assam state, India, 24 March 2015. Kaziranga will be closed to visitors for the next two days for a census of the rhinos commencing 25 March, in a previous census in 2013 in the park the population of the Indian rhinos was 2329. (Photo by EPA/Stringer)

A Pakistani scavenger girl writes on a notebook she collected from a garbage, while another girl sits next to her in Lahore, Pakistan, Wednesday, April 1, 2015. Thousands of children pick recyclable items from waste dumping points to earn living for their poor families. (Photo by K. M. Chaudary/AP Photo)

A 3-month-old ethnic Tujia baby girl is pictured next to her father as they wait for a traditional ethnic Tujia wedding feast during celebrations marking the Lunar New Year in Ziqiu town, Changyang county of China’s Hubei province, February 15, 2016. (Photo by Jason Lee/Reuters)

A man walks his dog as the sun sets in a park in Frankfurt, Germany, Monday, September 18, 2017. Cool damp weather is set to continue in this part of Germany for the next few days with temperatures in the mid teens Celsius. (Photo by Michael Probst/AP Photo)

A girl poses at an entrance of her house next to a bomb dropped by the U.S. Air Force planes during the Vietnam War, in the village of Ban Napia in Xieng Khouang province, Laos September 3, 2016. From 1964 to 1973, U.S. warplanes dropped more than 270 million cluster munitions on Laos, one-third of which did not explode, according to the Lao National Regulatory Authority. (Photo by Jorge Silva/Reuters)

A ceramic dog sleeps next to the gravesite of “Moses” at the Aspin Hill Memorial Park in Aspen Hill, Maryland August 25, 2015. Established in 1921, Aspin Hill contains the graves of more than 50,000 animals, from movies stars to WWI heroes to the dogs of former FBI Director J. Edgar Hoover. National Dog Day is celebrated in the United States on August 26. (Photo by Gary Cameron/Reuters)

A woman wearing a bikini stands next to fuel pumps as she waits to top up fuel at a petrol station in Kiev, Ukraine, September 26, 2015. One of the largest networks of petrol stations in Ukraine organized a campaign in which anyone who showed up in swimwear at a particular gas station during specified hours would receive free gasoline, according to representatives of the company. (Photo by Valentyn Ogirenko/Reuters)

A woman smokes a cigarette next to man wearing a mask during lunch hour at the central business district in Singapore September 29, 2015. The 3-hour haze Pollutant Standards Index (PSI) reached a high of 173 at 8am on Tuesday, according to the National Environment Agency. Slash-and-burn agriculture in neighboring Indonesia has blanketed Singapore in a choking haze for weeks. (Photo by Edgar Su/Reuters)