The Philippines is bracing itself for a long-haul battle against the haze, and expects smoke from Indonesia's forest and land fires to cause economic disruptions and respiratory illnesses in half of its territories for several months.
President Benigno Aquino's spokesman Herminio Coloma yesterday told reporters that the environment, science, health and transport ministries, as well as local disaster councils, were already preparing for "the possible long-term effects of… haze".
He said officials had issued health warnings, and hospitals have been put on alert.
The authorities have reported two deaths caused by asthma that might have been aggravated by the acrid haze enveloping the southern island of Mindanao since early this month.
Thick layers of smoke and particulate matter from thousands of wildfires in Indonesia's Sumatra and Kalimantan more than 1,200km away have been drifting to Mindanao and large parts of the central Philippines, affecting areas that are home to nearly 30 million people.
Weather officials said monsoon winds as well as wind patterns created by Typhoon Koppu, which recently ploughed across the main island of Luzon, could be causing the haze to drift towards the Philippines.
The haze has apparently reached parts of Luzon as well, disrupting operations at Clark, a major hub used by travellers from Singapore.
Poor airport visibility has already forced Philippine Airlines and Cebu Pacific to cancel flights between Manila and the cities of Cotabato, General Santos, Dumaguete and Tagbilaran, stranding thousands over the past 10 days.
No flight cancellations were reported yesterday, but at least six flights were delayed.
Pilots flying to Cebu, a key hub in the central Philippines, could see only 8km ahead, Agence France- Presse reported. At least nine airports have already grounded planes without instruments that allow pilots to land and take off in low to near-zero visibility.
Mr Rodante Joya, deputy director-general of the Civil Aviation Authority of the Philippines, told The Straits Times that the airlines were rearranging flights to haze-affected areas to take advantage of a 9am to 2pm window when visibility is clearest and to avoid cancellations.