The air quality in Sumatra appears to have improved from crisis levels in recent weeks, but conditions in parts of Kalimantan remained "hazardous" for much of yesterday.
The latest Pollutant Standards Index (PSI) readings from Indonesia's Meteorology, Climatology and Geophysics Agency (BMKG) showed that the Central Kalimantan capital of Palangkaraya peaked at 1,607 at 8am before dipping slightly to 1,488 at 6pm.
Pontianak, a city in West Kalimantan, clocked PSI levels as low as 114 in the morning, only to see them surge to 618 later in the day.
But Banjarbaru in the south of Kalimantan held steady in the moderate zone, registering at midnight a PSI of 26 that rose to 76.
Medan in North Sumatra saw significant improvements, recording a PSI reading of 95 at sundown.
But air pollution in the Riau capital of Pekanbaru worsened through the day, rising from a PSI level of 71 to 241.
A PSI reading over 350 is hazardous, while 151 to 250 is considered unhealthy.
The BMKG unit in Pekanbaru told The Jakarta Post yesterday that it recorded 1,465 hot spots in Sumatra, up from 1,025 on Thursday.
The epicentre was South Sumatra, where 1,296 hot spots were detected, said the agency.
The developments yesterday came after the PSI in Kalimantan and Sumatra surged to alarming levels the previous day, offering no respite from the haze for people in the two regions who were observing Hari Raya Haji on Thursday.
Parts of Indonesia, Singapore and Malaysia have been blanketed in a thick haze caused by the illegal burning of peatland and forests in Indonesia in recent weeks.
Schools were shut in Singapore yesterday as hazy conditions prevailed, sending the PSI to near-hazardous levels in the early part of the day.
In Malaysia, the haze in Johor hit "very unhealthy" levels, with Air Pollutant Index (API) readings of 201 in Pasir Gudang, and other areas in the state still showing "unhealthy" levels yesterday, reported The Star.
Malaysia's API and the PSI - used by Singapore and Indonesia - are closely related. Any reading above 100 is considered unhealthy.
Further north, Kuantan had "unhealthy" readings, while it was "moderate" in the Klang Valley.
Putrajaya registered 72; Cheras was at 53; Petaling Jaya, 64; Kuala Selangor, 52; and Shah Alam, 68. Most of Sarawak had "moderate" readings, while most of Sabah was in the "good" range except for Tawau, which registered a "moderate" API of 51.
This article was first published on Sep 26, 2015. Get a copy of The Straits Times or go to straitstimes.com for more stories.