Report title: Assessment of Extreme Air Pollution During Diwali 2026 in New Delhi: Air Quality Trends, Particulate Matter Concentrations, Firecracker Emissions and Monitoring Challenges
Reporting period: 7–9 November 2026 Study area: National Capital Territory of Delhi, India Subject: Air pollution, ambient air quality, particulate matter and the environmental consequences of Diwali celebrations.
1\. Executive Summary
New Delhi experienced its most polluted Diwali day in five years on 8 November 2026, highlighting the continuing severity of seasonal air pollution in the National Capital Territory. The Air Quality Index (AQI) reached 376 at 4:00 PM, representing the worst Diwali-day air quality since 2021.
The pollution situation was particularly concerning on the eve of Diwali, 7 November 2026, when the AQI reached 369, making it the most polluted Diwali-eve since 2016. Firecracker emissions emerged as the largest identified contributor to pollution on Choti Diwali, accounting for 41.1% of the total pollution load, according to the reported source-apportionment assessment.
Extremely high concentrations of fine particulate matter (PM2.5) were also recorded at several monitoring locations. The Indian Institute of Tropical Meteorology (IITM/ITM, as identified in the supplied report) recorded an average PM2.5 concentration of 671.1 micrograms per cubic metre (µg/m³) at midnight on 8 November. At individual monitoring stations, exceptionally high readings were reported at Jahangirpuri and Mundka.
However, the reliability of the overall air-quality assessment was affected by missing hourly data from several monitoring stations. Only 47 stations contributed to the average AQI calculation on Diwali day.
These observations demonstrate the combined challenges of episodic firecracker emissions, high particulate pollution and limitations in environmental monitoring during critical pollution events.
2\. Background and Context
Delhi regularly experiences severe air pollution during the post-monsoon and winter seasons. The problem is associated with several interacting factors, including:
* Vehicular emissions.
* Industrial and power-generation activities.
* Construction and road dust.
* Biomass and waste burning.
* Regional agricultural-residue burning.
* Firecracker emissions during festivals.
* Unfavourable meteorological conditions that restrict atmospheric dispersion.
Diwali celebrations often coincide with the seasonal deterioration of atmospheric conditions. Firecrackers release particulate matter, gaseous pollutants and various chemical compounds into the atmosphere, potentially intensifying already elevated pollution levels.
The observations reported for November 2026 indicate that Diwali-related emissions contributed to a substantial deterioration in Delhi's ambient air quality.
3\. Comparative Analysis of Diwali-Day AQI (2021–2026)
The reported AQI values show considerable year-to-year variation.
| Year | Diwali date | Diwali-day AQI |
| ---- | ----------- | -------------- |
| 2021 | 4 November | 382 |
| 2022 | 24 October | 312 |
| 2023 | 12 November | 218 |
| 2024 | 31 October | 328 |
| 2025 | 20 October | 345 |
| 2026 | 8 November | 376 |
Key findings
* The 2026 Diwali AQI of 376 was the highest since 2021.
* The 2026 value was 31 points higher than in 2025.
* Compared with 2023, when the AQI was 218, the 2026 value was 158 points higher.
* The 2021 AQI of 382 remained marginally higher than the 2026 value.
The comparison suggests that Delhi's Diwali air pollution has remained persistently severe, despite substantial fluctuations between years.
4\. Comparative Analysis of Post-Diwali AQI (2021–2026)
The post-Diwali air quality assessment provides further insight into the persistence of pollution following the festival.
| Year | Post-Diwali AQI |
| ---- | --------------- |
| 2021 | 462 |
| 2022 | 303 |
| 2023 | 358 |
| 2024 | 339 |
| 2025 | 351 |
| 2026 | 344 (4 PM) |
Important observations
* The post-Diwali AQI in 2026 reached 370 at 11:00 AM on Monday.
* It subsequently declined to 344 by 4:00 PM.
* The 2026 afternoon reading was lower than the 2025 value of 351.
* However, it remained higher than the 2022 and 2024 values.
* The 2021 post-Diwali AQI of 462 was the highest among the six years.
The findings indicate that although air quality improved during the afternoon of 9 November 2026, pollution levels remained considerably elevated.
5. Air Quality on Diwali Eve: An Alarming Situation
One of the most significant observations was the extremely poor air quality recorded on 7 November 2026, the day before Diwali.
The AQI reached 369, making it the most polluted Diwali-eve since 2016.
This observation is important because it suggests that air pollution had already reached a critical level before the main Diwali celebrations.
Possible contributing factors include:
* Early use of firecrackers.
* Accumulation of vehicular and industrial emissions.
* Road and construction dust.
* Regional sources of particulate pollution.
* Unfavourable atmospheric conditions.
The early deterioration in air quality indicates that pollution management strategies need to address the entire festival period rather than concentrating exclusively on Diwali night.
6. Firecrackers as a Major Source of Pollution
According to the source-apportionment findings reported in the supplied text, firecrackers were the largest identified contributor to pollution on Choti Diwali.
Contribution of firecrackers to the reported pollution load 41.1%
Reported contribution on the day before Diwali. This is a source-apportionment estimate, not a percentage of the AQI.
Firecrackers can release several pollutants and chemical constituents into the atmosphere, including:
* Fine particulate matter (PM2.5).
* Coarse particulate matter (PM10).
* Sulphur-containing compounds.
* Potassium-containing compounds.
* Metal-containing particles.
* Gaseous pollutants and other combustion products.
These emissions can increase atmospheric particulate concentrations and contribute to short-term deterioration in air quality.
The reported 41.1% contribution is particularly significant because it identifies firecracker emissions as a major pollution source during the pre-Diwali period.
However, the remaining pollution load may originate from other sources, including traffic, industrial activities, dust and regional emissions.
7. Extremely High PM2.5 Concentrations
Fine particulate matter (PM2.5) emerged as one of the most concerning aspects of the reported pollution episode.
PM2.5 refers to airborne particles with an aerodynamic diameter of 2.5 micrometres or smaller. Due to their small size, these particles can penetrate deep into the respiratory system and may enter the bloodstream.
7.1 Average PM2.5 concentration
At midnight on 8 November, ITM recorded its highest reported average PM2.5 concentration:
Reported average PM2.5 concentration 671.1 µg/m³
Recorded at midnight on 8 November 2026
This concentration indicates an extremely polluted atmospheric environment.
7.2 Station-wise PM2.5 observations
The supplied report identifies two locations with exceptionally high particulate concentrations.
| Monitoring station | Reported PM2.5 concentration | Time |
| ------------------------------------- | ---------------------------- | --------------------------- |
| Jahangirpuri, Northwest Delhi | 4,985 µg/m³ | Sunday night/Monday morning |
| Jahangirpuri (subsequent DPCC update) | 776 µg/m³ | 11 AM Sunday, as reported |
| Mundka, West Delhi | 3,744 µg/m³ | 2 AM |
| Mundka (subsequent reported reading) | 3,023.2 µg/m³ | Time not fully available |
These readings require careful interpretation because the supplied report indicates that some monitoring data were subsequently updated by the Delhi Pollution Control Committee (DPCC).
In particular, the Jahangirpuri reading of 4,985 µg/m³ and the subsequently reported DPCC value of 776 µg/m³ represent different reported observations and should not be treated as directly interchangeable.
The exceptionally high values nevertheless highlight the severity of localised particulate pollution during the festival period.
8. Chemical Constituents Detected in the Atmosphere
The reported monitoring observations confirmed the presence of traces of several chemical elements in the air, including:
* Lead (Pb).
* Potassium (K).
* Sulphur (S).
These elements may be associated with combustion emissions, fireworks and other anthropogenic sources.
Environmental significance
Lead: Lead-containing airborne particles are of concern because lead is a toxic heavy metal. Prolonged exposure can adversely affect the nervous system, kidneys and other organs.
Potassium: Potassium-containing compounds can be associated with firework compositions and combustion aerosols. Their presence may provide useful information for identifying certain sources of particulate emissions.
Sulphur: Sulphur-containing compounds released during combustion can contribute to atmospheric pollution and, under suitable chemical conditions, secondary particulate formation.
Mercury: Although concerns were raised about mercury contamination, officials reportedly stated that its presence could only be confirmed through a long-term study.
Therefore, mercury contamination should not be considered established based on the available observations.
9. Environmental Monitoring and Data Reliability Issues
An important concern identified in the report was the failure of several air-quality monitoring stations to provide complete hourly AQI data during the pollution episode.
Delhi has 60 air-quality monitoring stations managed by different agencies, including:
* Delhi Pollution Control Committee (DPCC).
* Central Pollution Control Board (CPCB).
* Indian Institute of Tropical Meteorology (IITM/ITM, as named in the report).
* India Meteorological Department (IMD).
One monitoring station had reportedly remained non-functional for several months.
9.1 Missing monitoring data
Initially, hourly data were unavailable from 35 monitoring stations.
Although DPCC subsequently updated data from some stations, several monitoring stations continued to show missing information during peak pollution hours.
Only 47 monitoring stations contributed to the average AQI calculation on Diwali day.
9.2 Implications of missing data
Incomplete monitoring data create several environmental assessment challenges:
1. Underrepresentation of pollution hotspots: Locations experiencing extremely high pollution may not be adequately represented in the citywide average.
2. Reduced accuracy: Missing observations may affect the reliability and representativeness of the overall AQI assessment.
3. Difficulties in source identification: Incomplete hourly data can make it difficult to identify the timing and intensity of pollution episodes.
4. Challenges in public communication: Accurate and timely information is essential for issuing health advisories and pollution-control warnings.
5. Limitations in policy evaluation: Reliable monitoring data are necessary to assess the effectiveness of environmental regulations and pollution-control interventions.
A robust monitoring network is therefore essential for effective urban air-quality management.
10. Public Health and Environmental Implications
The severe deterioration in Delhi's air quality raises significant public-health concerns.
10.1 Human health
Exposure to high concentrations of PM2.5 and other airborne pollutants can cause:
* Irritation of the eyes, nose and throat.
* Coughing and breathing difficulties.
* Asthma attacks and worsening of existing respiratory diseases.
* Reduced lung function.
* Increased cardiovascular stress.
* Greater health risks among children, elderly people and individuals with pre-existing respiratory or cardiovascular conditions.
Short-term exposure to extremely polluted air can be particularly harmful to vulnerable populations.
10.2 Ecological consequences
Air pollution also has implications for urban ecosystems.
* Deposition of airborne particles can contaminate soil and vegetation.
* Certain pollutants can interfere with plant physiological processes.
* Toxic metals may accumulate in environmental compartments.
* Atmospheric pollutants can contribute to changes in soil and water chemistry.
* Reduced visibility can affect urban environmental quality.
The ecological impacts depend on pollutant composition, exposure duration and environmental conditions.
11. Major Findings of the Report
The major findings from the reported observations are summarised below.
| Indicator | Major observation |
| ------------------------ | ------------------------------------------------------- |
| Diwali AQI 2026 | 376 at 4 PM |
| Diwali pollution ranking | Worst Diwali since 2021 |
| Diwali-eve AQI | 369 |
| Diwali-eve ranking | Most polluted since 2016 |
| Post-Diwali AQI | 370 at 11 AM, declining to 344 at 4 PM |
| Firecracker contribution | 41.1% of reported pollution load |
| Average PM2.5 | 671.1 µg/m³ at midnight |
| Jahangirpuri PM2.5 | Peak reported value of 4,985 µg/m³ |
| Mundka PM2.5 | 3,744 µg/m³ |
| Chemical constituents | Lead, potassium and sulphur traces confirmed |
| Monitoring stations | 60 total; only 47 contributed to Diwali-day average AQI |
| Mercury | Requires long-term investigation for confirmation |
12. Recommendations for Air Pollution Management
Based on the reported findings, the following measures are recommended.
12.1 Control of firecracker emissions
* Strict enforcement of existing restrictions on prohibited firecrackers.
* Promotion of environmentally responsible festival celebrations.
* Public awareness campaigns regarding the health impacts of firecracker emissions.
* Strengthening community participation in pollution-control programmes.
12.2 Strengthening air-quality monitoring
* Ensure continuous functioning of all air-quality monitoring stations.
* Introduce real-time data validation and quality-control mechanisms.
* Investigate missing hourly monitoring records.
* Increase monitoring capacity in pollution hotspots.
* Improve coordination among DPCC, CPCB, IITM and IMD.
12.3 Reduction of other pollution sources
* Improve public transportation and reduce unnecessary private vehicle use.
* Control construction and road dust through appropriate management.
* Strengthen industrial emission monitoring.
* Prevent open burning of municipal waste and biomass.
* Promote cleaner energy technologies.
12.4 Public health protection
* Issue timely health advisories during severe pollution episodes.
* Reduce outdoor physical activities during periods of extreme pollution.
* Protect children, older people and individuals with respiratory problems.
* Improve access to clean indoor air in schools, hospitals and public institutions.
* Strengthen public awareness about PM2.5 exposure and its health consequences.
12.5 Long-term environmental research
* Conduct long-term studies on the chemical composition of atmospheric particulate matter.
* Investigate the presence and environmental distribution of heavy metals.
* Examine the effects of atmospheric pollutants on urban vegetation and biodiversity.
* Conduct source-apportionment studies to distinguish the contributions of industrial, vehicular, agricultural and festival-related emissions.
* Evaluate the relationship between meteorological conditions and seasonal air pollution.
13. Discussion
The reported air-quality observations from Delhi during Diwali 2026 demonstrate that urban air pollution is a complex environmental problem involving multiple emission sources.
The AQI of 376 on Diwali day and 369 on Diwali-eve indicate that the city experienced a substantial pollution burden during the festival period. The reported contribution of firecrackers (41.1%) further highlights the importance of controlling festival-related emissions.
However, it would be scientifically inappropriate to attribute the entire pollution episode to firecrackers alone. Vehicular emissions, industrial activities, construction dust, biomass burning and unfavourable atmospheric conditions may also contribute significantly to the deterioration of air quality.
The exceptionally high PM2.5 concentrations reported at Jahangirpuri and Mundka indicate that pollution intensity can vary considerably between locations. Therefore, citywide average AQI values alone may not adequately represent the exposure experienced by residents of individual neighbourhoods.
Another important issue is the incomplete reporting of monitoring data. The failure of several stations to provide hourly observations during peak pollution periods raises questions about the representativeness and reliability of the available dataset.
From an environmental management perspective, the findings emphasise the need for integrated pollution-control strategies involving government agencies, industries, scientific institutions and local communities.
14. Conclusion
Delhi's Diwali 2026 pollution episode represents a significant environmental and public-health concern. With an AQI of 376, the city experienced its most polluted Diwali day since 2021. The deterioration in air quality had already begun before the festival, as indicated by the Diwali-eve AQI of 369.
The reported contribution of firecrackers to 41.1% of the pollution load on Choti Diwali, together with exceptionally high PM2.5 concentrations at selected monitoring stations, highlights the seriousness of festival-related atmospheric pollution.
The detection of lead, potassium and sulphur also emphasises the importance of investigating the chemical composition of airborne particulate matter. Furthermore, incomplete monitoring data demonstrate the need to strengthen environmental surveillance systems.
Ultimately, improving Delhi's air quality requires more than temporary restrictions during festivals. It demands sustained pollution-control policies, effective industrial and vehicular emission management, reliable environmental monitoring, scientific research and active public participation.
Clean air should be considered an essential environmental right and a fundamental requirement for public health, ecological sustainability and overall quality of life.
Suggested AQI interpretation: Under India's National Air Quality Index classification, an AQI between 301 and 400 falls under the Very Poor category. Therefore, the reported Diwali AQI of 376 indicates very poor air quality.
Suggested References for Further Scientific Reading:
The following authoritative sources can support further scientific discussion and academic development of this report.
Central Pollution Control Board (CPCB), Government of India – National Air Quality Index and air-quality monitoring: [CPCB official website](https://cpcb.nic.in/?utm_source=chatgpt.com).
World Health Organization (WHO) – Global Air Quality Guidelines (2021): [WHO Air Quality Guidelines](https://www.who.int/publications/i/item/9789240034228?utm_source=chatgpt.com).
Ministry of Environment, Forest and Climate Change – Environmental policies and air pollution management: [MoEFCC official website](https://moef.gov.in/?utm_source=chatgpt.com).
United States Environmental Protection Agency – Particulate Matter (PM2.5 and PM10): [Particulate Matter Pollution](https://www.epa.gov/pm-pollution?utm_source=chatgpt.com).
Indian Institute of Tropical Meteorology – Atmospheric research and air-quality information: [IITM official website](https://www.tropmet.res.in/?utm_source=chatgpt.com).
Overall assessment: The 2026 Diwali pollution episode provides an important case study for understanding the interaction between festival-related emissions, urban pollution sources, atmospheric conditions and environmental monitoring challenges in Indian metropolitan cities. It also offers a strong basis for further research into atmospheric pollution, human health and urban environmental sustainability.
