High above the vast Indonesian island of Sumatra, satellites identify hundreds of plumes of smoke drifting over the oil palm plantations and rain forests.
Monsoon winds sweep them north and east toward Singapore, Malaysia and deep into Cambodia, Laos and Thailand. Southeast Asian cities have been choking for weeks, wreathed in an acrid, stinking blanket of half-burned vegetation mixed with industrial pollution, car exhaust fumes and ash.
From Palangkarya in Borneo to Kuala Lumpur in Malaysia, the air has been thick, the sun a dull glow and face masks obligatory.