Hyderabad's air quality deteriorated beyond the hazardous threshold on Monday (October 20, 2025) night as firecrackers were burst across the city beginning around 7 p.m. The Air Quality Index (AQI), measured in terms of PM 2.5 microns, worsened from moderate to unhealthy levels within an hour as a stiff easterly wind carried smoke and particulate matter through several neighbourhoods.

As loud bursts and trails of arced fireworks illuminated the night sky, a sulphurous smell hung over Sanathnagar, Ameerpet, Attapur, Kukatpally, Jubilee Hills and surrounding areas. By 9 p.m., air quality monitors showed alarming readings, with Kukatpally recording a PM 2.5 level of 945 -- far exceeding the hazardous threshold of 301. Somajiguda registered 467, Secunderabad 362, and Vittal Rao Nagar 511, while most sensors across the city blinked above 250, rendering the air unsafe for breathing. Even the University of Hyderabad, located on the city's outskirts, reported 661 at 9 p.m.

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By 10 p.m., the sensor at Kukatpally logged PM 2.5 at 1133 µg/m3 nearly four times the hazardous levels in India. At the same time, the sensors in most parts of central Hyderabad measured particulate matter pollution at above 300 mark. Particulate matter pollution is considered extremely dangerous due to the small size of the particles that can be easily inhaled and then absorbed by the body.

The Telangana State Pollution Control Board's online monitors had gone offline on Sunday night. When the sensors became operational on Monday evening, the Sanathnagar sensor showed 252 at 8 p.m., peaking at 500 by 10 p.m. and remaining at that level until midnight. Incidentally, the United States Environment Protection Agency's scale to measure PM2.5 maxes out at 500. By 1 a.m., it dropped marginally to 442 and continued to stay hazardous at 315 even at 2 a.m., long after the cracker-bursting had ceased. By 3 a.m., the air quality improved substantially but still remaining in the poor category.

AQI deteriorates to hazardous levels for few hours in Hyderabad as Deepavali celebrations light up the night