Students stand on the roof of a wooden boat as haze blankets the Musi River while they travel to school in Palembang, on Indonesia's Sumatra island, September 10, 2015. Indonesia is investigating 10 firms over worsening forest fires that have created a blanket of smog over Southeast Asia, threatening them with sanctions if they are found responsible, a government minister said on Tuesday. The thick haze from Indonesia's Sumatra and Kalimantan islands has forced the repeated cancellation of flights in the area and pushed air quality to unhealthy levels in neighbouring Singapore and Malaysia. (Photo by Reuters/Beawiharta)

In this November 28, 1966 file photo, one of the 10 beagles involved in the first test of the Veterans Administration Hospital in East Orange, N.J. smokes a cigarette through a machine linked to its windpipe by a plastic tube to test any link between smoking and emphysema. (Photo by AP Photo)

A model has makeup applied backstage prior to Lebanese designer Zuhair Murad fashion show held during the Haute Couture Fall/Winter 2014-2015 fashion collections in Paris July 10, 2014. (Photo by Philippe Wojazer/Reuters)

Israelis in costumes spray water on each other during the annual Tel Aviv Water War on Hbima Square in Tel Aviv, Israel,10 July 2015. The annual water fight is on his 11th edition. (Photo by Abir Sultan/EPA)

An illustration showing scarecrows pulling a firewood cart beside a road is on display at Kakashi no Sato, or the Scarecrow's Hometown on September 10, 2014 in Himeji, Japan. In this district of Yasutomi in Himeji city, over 100 of scarecrows stand in farmlands and abandoned houses to illustrate the good old Japanese countryside and attract visitors. (Photo by Buddhika Weerasinghe/Getty Images)

Actors dressed up as zombies walk around while posing for photos with passers-by in New York's Times Square on Friday, October 10, 2014 as a promotion for the season premiere of AMC's “The Walking Dead” this Sunday, October 12, 2014. (Photo by Gordon Donovan)

A woman views the painting “Alegory of Love” by Marc Dennis at the “Hello! Exploring the Supercute World of Hello Kitty” museum exhibit in honor of Hello Kitty's 40th anniversary, at the Japanese American National Museum in Los Angeles, California October 10, 2014. (Photo by Lucy Nicholson/Reuters)

A Zombie Santa is pictured Death Yard Haunted Attraction in Hendersonville, Tennessee December 10, 2014. The Nashville-area haunted house is getting into the Christmas spirit this weekend, with Zombie Santa, his undead elves and a demonic reindeer going on the attack for fun and charity. (Photo by Harrison McClary/Reuters)