A view of the vehicles plying the causeway to Malaysia shrouded by haze 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)





A yacht passes a marina next to a luxury condominium project shrouded by haze in Singapore September 29, 2015. (Photo by Edgar Su/Reuters)





Cable cars moving towards the island resort of Sentosa are shrouded by haze in Singapore September 29, 2015. (Photo by Edgar Su/Reuters)





Office workers wearing masks walk during lunch hour at the central business district in Singapore September 29, 2015. (Photo by Edgar Su/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. (Photo by Edgar Su/Reuters)





Office workers wearing masks walk during lunch hour at the central business district in Singapore September 29, 2015. (Photo by Edgar Su/Reuters)





Office workers wearing masks walk during lunch hour at the central business district in Singapore September 29, 2015. (Photo by Edgar Su/Reuters)





Motorists wearing masks cross a junction during lunch hour at the central business district in Singapore September 29, 2015. (Photo by Edgar Su/Reuters)





Office workers wearing masks walk during lunch hour at the central business district in Singapore September 29, 2015. (Photo by Edgar Su/Reuters)





Planes sit on the tarmac in Singapore's Changi Airport September 29, 2015. The 3-hour haze Pollutant Standards Index (PSI) reached a high of 245 at 1300 SGT (0500 GMT) on Tuesday, according to the National Environment Agency. (Photo by Edgar Su/Reuters)





A Jetstar plane taxis on the tarmac at Singapore's Changi Airport September 29, 2015. (Photo by Edgar Su/Reuters)





A woman watches as a Singapore Airlines plane prepares to take off, from a viewing gallery in Singapore's Changi Airport September 29, 2015. (Photo by Edgar Su/Reuters)





People look at planes from a viewing gallery in Singapore's Changi Airport September 29, 2015. (Photo by Edgar Su/Reuters)





A tourist bus passes the skyline of the central business district shrouded by haze in Singapore September 29, 2015. (Photo by Edgar Su/Reuters)





Women watch vessels pass an anchorage area shrouded by haze in the southern coast of Singapore September 29, 2015. (Photo by Edgar Su/Reuters)





People are silhouetted by the setting sun as they look out from the observatory tower of the Marina Bay Sands hotel shrouded by haze in Singapore September 29, 2015. (Photo by Edgar Su/Reuters)





People wearing masks pass the Singapore Flyer Observatory Wheel shrouded by haze in Singapore September 29, 2015. (Photo by Edgar Su/Reuters)





A man uses his mobile phone against a backdrop of vessels anchored at an anchorage point in the southern coast of Singapore September 29, 2015. (Photo by Edgar Su/Reuters)





Youths have a picnic near the Singapore Flyer Observatory Wheel shrouded by haze in Singapore September 29, 2015. (Photo by Edgar Su/Reuters)





Youths have a ball game against a backdrop of the Singapore Flyer Observatory Wheel (C, rear) shrouded by haze in Singapore September 29, 2015. (Photo by Edgar Su/Reuters)





Students of State Police School (SPN) run amid haze while attending a physical exercise in Pekanbaru, Indonesia Riau province, September 30, 2015 in this picture taken by Antara Foto. Indonesia has sent nearly 21,000 personnel to fight forest fires raging in its northern islands, the disaster management agency said on Tuesday, but smoke cloaks much of the region with pollution readings in the "very unhealthy" region in neighbouring Singapore. (Photo by Rony Muharrman/Reuters/Antara Foto)





Office workers wearing masks pass a man in a clinic during lunch hour at the central business district in Singapore September 29, 2015. (Photo by Edgar Su/Reuters)