With AQI levels in the state capital lingering in the hazardous zone on Wednesday, MPPCB officials say stability class wind velocity and other meteorological factors are driving up the index.

The AQI levels in the state capital averaged out at a very unhealthy 282 across the three monitoring stations at Idgah, TT Nagar, and Paryavaran Bhawan.

While the readings at TT Nagar and Idgah ranged between 250–275, the monitoring station at Paryavaran Bhawan recorded the AQI at 320 at 7 PM on Wednesday.

District Pollution Official Brajesh Sharma attributed the high AQI levels to an amalgam of meteorological factors, including very low wind velocity falling in the stability class, which results in the stagnation of microscopic particulate matter—PM2.5 and PM10—in the city air.

Relative humidity and dryness in the atmosphere were cited as other reasons polluting the air, apart from vehicular emissions, traffic dust, crop residue burning, and cultural factors involving fireworks.

The official did not rule out the effects of temperature inversion, which makes warmer air rise during colder months and acts like a lid on colder air, stagnating particulate matter.

Irrespective of the cause, stagnation of PM2.5 and PM10 is hazardous to human and animal health, as the invisible particles, mostly aerosols, invade the respiratory tract, causing breathing difficulties and coughing.

The pollutants are especially dangerous to people with underlying respiratory and cardiovascular disorders, as well as those susceptible to allergies.

Medical practitioners have advised people with such ailments to stay indoors and keep doors and windows closed. Morning walkers are also advised to wear masks to avoid discomfort or more serious repercussions during colder months.