Air quality in Pekanbaru, the capital of the Indonesian province of Riau, deteriorated to an all-time low yesterday as choking haze forced the cancellation of flights and closure of schools.

The PM10 Pollutant Standards Index (PSI) in Pekanbaru crossed the 700-mark yesterday. In the region's worst haze crisis in 2015, Pekanbaru had registered a PSI reading of 600.

In Singapore, air quality was unhealthy yesterday. As of 8pm, the 24-hour PSI for all regions was over 100. The one-hour PM2.5 concentration reading was in the "elevated" range of 78 at 8pm, though it did not deter the crowds watching the Formula One race.

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