A view shows the city skyline shrouded by haze in Kuala Lumpur, Malaysia, September 13, 2019. Southeast Asia has suffered for years from annual bouts of smoke caused by slash-and-burn clearances of forests for farms and palm oil plantation land, raising worries about public health and the impact on tourism.

REUTERS/Lim Huey Teng 

Students cover their faces with masks at a school as haze shrouds Kuala Lumpur, Malaysia, September 13, 2019. Malaysia has said smoke from fires on Indonesia's Sumatra and Borneo islands over the past month has drifted over the border, forcing it to close schools and issue public health alerts.

REUTERS/Lim Huey Teng 

A man sits on a bench as the coastline shrouded by haze is seen in Singapore September 12, 2019. REUTERS/Feline Lim 

A tourist poses for a picture at Kuala Lumpur Tower with the city skyline in the background shrouded by haze, in Kuala Lumpur, Malaysia, September 13, 2019. REUTERS/Lim Huey Teng 

A view of the city skyline shrouded by haze in Kuala Lumpur, Malaysia, September 11, 2019. REUTERS/Lim Huey Teng 

A tourist poses for a picture with the city skyline shrouded by haze at Kuala Lumpur Tower in Kuala Lumpur, Malaysia, 11 September 2019. REUTERS/Lim Huey Teng 

A view of the city skyline shrouded by haze in Kuala Lumpur, Malaysia, September 11, 2019. REUTERS/Lim Huey Teng 

A tourist wearing a mask to protect against the haze is seen in Singapore September 13, 2019. REUTERS/Feline Lim 

A tourist looks at the city skyline shrouded by haze at Kuala Lumpur Tower in Kuala Lumpur, Malaysia, September 13, 2019. REUTERS/Lim Huey Teng 

A boy wearing a mask to protect himself against the haze is seen in Singapore September 13, 2019. REUTERS/Feline Lim 

Petronas Twin Towers are shrouded by haze in Kuala Lumpur, Malaysia, September 9, 2019. REUTERS/Lim Huey Teng