Thousands of protesters have taken to the streets of Sydney on Wednesday calling for action on climate change and health as bushfires have hindered the city's air quality. /Getty Images

Organizers estimate that about 20,000 joined the march, accusing the government of inaction. /Getty Images

On Tuesday, the level of PM 2.5 particles in the air of the harbor city reached as high as 10 times the normal level, causing chaos and setting off smoke alarms and marring visibility. /Getty Images

Bushfires have been raging in New South Wales and Queensland for weeks, killing six people and destroying over 700 homes. /Getty Images