Why does Sydney smell like smoke this morning?

An air quality warning has been issued for Western Sydney as firefighters are completely engulfed in flames.

Two hazard mitigation burns are underway in Kur-ring-gai Chase National Park and Katoomba.

Air quality warnings are currently in force for Richmond and Penrith, with haze spreading across the city and its residents.

Many residents had a sleepless night due to the strong smoke smell.

Residents in affected areas are advised to take precautions by closing windows and doors until air quality improves.

These burns are one of many risk mitigation operations undertaken each year by NSW National Parks and Wildlife Service, many with assistance from the NSW Rural Fire Service and Fire and Rescue NSW.

What is backburn?

Backburning, also called controlled burning, is a technique used in firefighting to reduce the severity and spread of forest fires. It involves deliberately lighting fires under controlled conditions to burn vegetation in a controlled manner.

The purpose of backburning is to create a barrier of already burned land that the wildfire cannot cross, reducing the need for fuel for the advancing fire and creating a safer area for firefighters to work from. b

By reducing the amount of fuel available to the wildfire, backburning can help control the fire and protect lives, property and natural habitats.