The decision to close schools came as the three-hour pollutant standards index, which measures air quality, moved from "very unhealthy" to "hazardous" by Friday morning. The government and community organizations responded to the worst air pollution recorded this year by distributing face masks to the vulnerable and warning citizens to avoid going outside.
The worsening air conditions, brought on by prevailing winds from Indonesia, came as the multi-ethnic city state was celebrating the Muslim Eid al-Adha holiday and will celebrate the Chinese mooncake festival on Sunday.
Singapore, Malaysia and Indonesia have been impacted by nearly three weeks of haze, which is an annual occurrence as dense forests in Indonesia's Sumatra and Kalimantan islands are cleared for palm plantations during the dry season.
Haze creates diplomatic rift
The haze has led to a growing dispute between Singapore and Indonesia, which was exacerbated by comments from Indonesian Vice President Jusuf Kalla that neighboring countries "already enjoy 11 months of clean fresh air from Indonesia." He suggested countries like Singapore could handle one month of dangerous air quality to allow forest clearing in Indonesia.
Singapore's foreign minister, K. Shanmugam, responded that the country takes "takes the matter seriously" and offered Indonesia help to combat the forest fires, many of which are caused by illegal burning.
"Yet, at the same time, we are hearing some shocking statements made, at senior levels, from Indonesia, with a complete disregard for our people, and their own," Shanmugam said.
Indonesia faces an uphill battle stopping slash-and-burn agriculture. On Tuesday, the country's environment and forestry ministry suspended or revoked the licenses of four plantation companies for setting illegal fires to clear land. Another 27 companies are also being investigated and some 140 people are being questioned for illegal fires.
However, the problem is exacerbated by corruption, poor enforcement and governance and a lack of political will in Indonesia to address illegal forest clearing.
cw/sms (AP, Reuters)