Pune air quality takes a brief hit on Diwali, recovers as winds pick up: IITM

The observation and data also align with the analysis by Climate Trends, a research-based consulting and capacity-building initiative specialising in climate and sustainable development issues, that found PM 2.5 levels showed a slight dip compared to the pre-Diwali phase, averaging 67.9 µg/m³ in 2025 and 57.4 µg/m³ in 2024, likely reflecting temporary atmospheric dispersion before the night-time pollution spike.

In the post-Diwali phase, the data reveals a different trend: 2024 recorded a sharper rise to about 70 µg/m³, while 2025 saw a slightly lower average of around 66 µg/m³. This suggests that despite a higher baseline level, Pune experienced less intense post-Diwali pollution in 2025, potentially due to better dispersion conditions or reduced firecracker activity.

‘Missing data’

According to the Central Pollution Control Board’s Sameer app, moderate levels of AQI for three out of four Diwali days, with rains marking the last day, October 23, where a lower AQI is seen. On the application, it records that only five out of 13 existing monitoring stations are functional. “CPCB data dashboard shows out of 10 IITM and three MPCB continuous air quality monitoring stations, data is available only for nine monitors, while four monitors, namely Karve Road MPCB, MIT Kothrud IITM, Alandi IITM and Bhosari IITM, are inactive. In addition to this, readings from Revenue Colony, Shivajinagar IITM Monitor do not have any data recorded on October 22 and 23,” according to experts at Parisar, a civil society organisation advocating for sustainable development.

Pune air quality

“Last year, SPPU MPCB monitor recorded the highest PM 10 readings at 317 ug/m3 and equally alarming PM 2.5 readings at 268 ug/m3. Hadapsar IITM monitor recorded the highest PM 10 at 337 ug/m3 in 2024. Last year’s maximum reading seems comparatively much higher than this year’s. It is important to note here that according to our National Ambient Air Quality Standards, the daily limit for PM 10 is 100 ug/m3 and PM 2.5 is 60 ug/m3. So technically, except for one or two odd monitors or days, we have crossed the safe limits for most of the Diwali days. Our standards are way more lenient than the WHO standards, which peg the PM 10 limit at 45 ug/m3 and PM 2.5 limit at 15 ug/m3,” Hema Chari, Pune Air Action Hub, said.

Sharmila Deo of Parisar said that compared to last year, the readings of many monitors show a drop. “This could be attributed to the fact that it rained during the four Diwali days, thereby reducing pollution automatically. Data and analysis of firecracker sales are crucial to be able to say if causal factors such as pollution from firecrackers really reduced this year,” Deo said.

Shweta Vernekar, Senior Programme Associate, Parisar, also emphasised that good, consistent data can help study trends and inform decisions and actions to reduce pollution.

“Missing data or inactive monitors are problematic. The Shivajinagar Monitor has consistently recorded high readings in the past, attributed to ongoing metro and flyover construction. However, it has given very off readings on Diwali days, and no data has been recorded for much of October. Also, the gap between the active monitor number in the app and the dashboard, both managed by CPCB is again a source of confusion. It is important to address these gaps urgently and also explain why readings may go wrong. Citizens and civil society organisations rely on this data for advocacy, and any trust deficit on the data itself harms the cause of clean air,” Vernekar said.

Relevance of Air Quality Index in terms of health effects during Diwali

Moderate AQI, as per the app, indicates breathing discomfort to people with lung disorders, asthma and heart diseases. Experts noted that this is a conservative health advisory of immediate effects, and does not indicate much about the cumulative, long-term impact of consistently breaching air pollution levels.

“The relevance of AQI in terms of health effects may be completely different during Diwali because of the specific contents of the firecrackers. Usually, a mild to moderate AQI may sound relevant to only those at risk, like patients with pre-existing respiratory and cardiac conditions facing worsening of their health issues during this period. However, it is important to remember that the hazardous contents of firecrackers change the air quality in a far worse way.

Compared to ambient and vehicular air pollution and cigarette smoke, firecrackers contain 40 to 400 times more poisonous substances. Contents like sulphur, potassium nitrate, charcoal, and heavy metal particles in firecrackers have effects on eyes, skin, heart, lungs and also carcinogenic capacity. The current weather in Pune has led to trapping of these chemicals in the respirable range due to smog. Acid rain secondary to this is not good for the environment either,” Dr Aparna Birajdar, consultant pulmonologist who is also a member of Pune Air Action Hub, said.