Sydney air pollution sets off fire alarms, AQI goes past 'hazardous'

The number of people seeking treatment at Sydney hospitals increased by about 25%

Bushfire smoke smothered Sydney on Tuesday, setting off fire alarms, suspending ferry services and triggering health warnings over choking air pollution.

The Sydney Opera House and harbor bridge were barely discernible through the thick haze enveloping the city, with smoke stinging the eyes and making it difficult to breathe.

The Air Quality Index compiled by the state environment department reached as high as 2,552 in some eastern suburbs -- soaring past the “hazardous” threshold of 200. The pollution has been so bad it has set off smoke alarms in office buildings across the CBD, while ash has been washing up on the