Delhi pollution is the stuff of nightmares. But Kolkata’s air quality lately also shows cause for concern

The air pollution in Delhi is now the stuff of nightmares and international headlines, but the air quality index in Kolkata has not been much better either, as November 2025 draws to a close.

As Delhi made headlines for its severe smog episodes this year during the onset of winter, Kolkata moved through a week marked by sharp swings in air quality from 20 to 28 November.

In fact, the cleanest air Kolkata breathed in the past week was an Air Quality Index (AQI) of 144, while Delhi’s best was 193. At the other end of the scale, Kolkata’s most toxic hour touched 417, only a few steps behind Delhi, which recorded 494.

The narrow gap between the two cities is a warning that Kolkata is far from safe. The city has not grabbed national attention yet, but the city’s poor air quality has been causing health concerns and spikes in pollution-related illnesses such as persistent cough in children.

Understanding AQI categories and their health impact

The Air Quality Index provides a clear grading of pollution levels and the associated health effects. A reading of 51 to 100 is satisfactory and may cause mild discomfort to sensitive groups.

The moderate band between 101 and 200 can lead to breathing discomfort among people with respiratory illnesses.

Poor air between 201 and 300 tends to irritate the throat and eyes for most individuals.

Very poor, between 301 and 400, is linked to reduced lung capacity and aggravated asthma.

AQI above 400 is labelled severe and is considered harmful for everyone, often leading to chest tightness and worsening symptoms for those with heart or lung conditions.

While Kolkata dealt with its own bouts of poor and very poor air, Delhi’s prolonged emergency kept the national spotlight fixed on pollution. The capital recorded a peak AQI of 494 on 27 November and struggled to move out of the severe band. Even its lowest reading of the week, at 193, remained in the poor category.

Kolkata’s highs and lows from 20 to 28 November

The city’s most troubling moment came on 23 November, when the AQI climbed to 417 shortly after midnight, pushing Kolkata briefly into the severe category. Although the numbers eased later, the improvement did not last.

Over the next few days, the AQI moved between poor and very poor levels, with only short spells in the moderate range. The cleanest point appeared on 27 November, at 12.04 pm, when the AQI dipped to 144, yet even this fell within the moderate band. The AQI climbed again soon after, leaving little breathing room for sensitive groups.

Given that the recorded AQI was more than 200 on most of the days in the past week, the citizens were exposed to hazardous air, causing harm to both lungs and heart.

Health experts concerned

Doctors across the city have begun noticing the impact of these fluctuations.

“Kolkata’s AQI remains higher than the average levels, and it fluctuates depending on the prevailing weather conditions. Children and the elderly are being affected the most. We are noticing a rise in cases of bronchitis, asthma, persistent cough, and viral infections. Post-viral recovery is also taking longer than usual,” said Sauren Panja, senior consultant and administrative lead of Critical Care Services at Narayana RN Tagore Hospital in Mukundapur.

What this means for Kolkata 

The week’s data shows that Kolkata avoided the relentless, hazardous air gripping Delhi, but its own AQI swings remain a cause for concern. The fluctuating levels can trigger breathing trouble among children, older adults and people with chronic lung conditions. With colder nights ahead and slower wind dispersal likely, the city may continue to see unstable air in the coming weeks. Doctors warn that if the pattern persists, winter illnesses may intensify, especially for those already recovering from respiratory infections.