Project Brief
View on GitHubProblem Statement
How does India's air quality crisis translate into measurable health burden — and which cities and seasons are worst?
Tools & Stack
Methods
Epidemiological data synthesis, source apportionment, AQI trend analysis, city-level benchmarking against WHO guidelines
Output
Interactive AQI explorer with health burden estimates, seasonal patterns, and city comparisons
Section 01 · The Scale
How bad is it, really?
Air quality data is messy — different countries measure differently, and seasonal spikes dominate headlines. Let's start with the number that cuts through it: annual average PM2.5, the particle most harmful to human health.
Annual PM2.5 — India's cities vs WHO guideline
WHO 2021 Air Quality Guideline: 5 µg/m³ annual PM2.5. India's own national standard: 40 µg/m³ — itself 8× the WHO limit. IQAir 2023 data. Ground-level monitors + satellite-corrected estimates.
IQAir World Air Quality Report 2023 · WHO Global Air Quality Guidelines 2021 (WHO/EURO:2021-4507-43851-61789)
India's AQI scale — CPCB categories
CPCB AQI categories apply to real-time 24-hr readings, not annual averages. Delhi regularly reaches 400–500 in winter.
Central Pollution Control Board (CPCB) — National AQI framework. cpcb.nic.in
IQAir 2023: Top 10 most polluted cities globally
Annual average PM2.5 µg/m³. 9 of the 10 most polluted cities are in India.
IQAir World Air Quality Report 2023 · iqair.com/world-air-quality-report
Section 02 · The Health Toll
1.67 million deaths a year.
What does that actually mean?
The State of Global Air 2024, published by the Health Effects Institute and IHME, is the most comprehensive annual analysis of air pollution's health burden. It uses the Global Burden of Disease methodology — not projections, not estimates based on old data.
Premature deaths in India attributable to air pollution, 2021
State of Global Air 2024, IHME/HEI [1]
Average life expectancy lost nationally due to PM2.5 exposure
AQLI 2023 — University of Chicago EPIC [2]
Life expectancy lost in Uttar Pradesh (highest in India)
AQLI 2023 — University of Chicago EPIC [2]
Share of India's disease burden from air pollution alone
State of Global Air 2024 [1]
What's killing people: outdoor vs indoor pollution
Approximate breakdown of India's ~1.67M air-pollution deaths in 2021. Note: figures overlap slightly (some people exposed to both outdoor + indoor sources); totals reflect independent burden calculations.
State of Global Air 2024 (IHME/HEI) · stateofglobalair.org · PMUY progress: PIB India
Life expectancy lost to PM2.5 — state by state
AQLI 2023 estimates years of life expectancy lost if a person spends their lifetime at current PM2.5 levels. This is a cumulative exposure model, not year-over-year loss. Based on peer-reviewed epidemiology linking PM2.5 to mortality rates.
AQLI 2023 — Air Quality Life Index, University of Chicago Energy Policy Institute (EPIC) · aqli.epic.uchicago.edu [2]
Section 03 · Your Numbers
What does your city's air cost you?
This calculator applies the AQLI epidemiological model at the individual level. The rate used (0.98 years of life per 10 µg/m³ above WHO guideline) is derived from the peer-reviewed methodology in Pope et al. (2009) and Crouse et al. (2012), the same sources underlying AQLI.
Select your city
Estimated real-time AQI range (winter)
AQLI methodology: Pope et al. (2009), Crouse et al. (2012). Model applies population-level epidemiology to individual exposure — treat as directional, not clinical.
Section 04 · The Winter Crisis
Why India's air turns
toxic every October.
The Diwali + stubble-burning season coincides with a meteorological inversion layer that traps pollutants at ground level. This combination drives Delhi's air quality from Poor to Severe within days — and the causes are documented in peer-reviewed research.
Stubble burning — Punjab & Haryana
After the Kharif harvest (Oct–Nov), farmers burn paddy stubble to clear fields for the next crop. Satellite fire counts from VIIRS/MODIS routinely show 40,000–70,000 fire events in Oct–Nov. Wind carries the smoke 200–300km southeast into Delhi.
Stubble burning contributes 20–40% of Delhi's PM2.5 on peak smoke days (TERI analysis, 2023).
TERI Institute analysis 2023 · NASA FIRMS fire data (VIIRS) [3]
Diwali fireworks — acute PM spike
Annual fireworks on Diwali night cause the sharpest single-night PM2.5 spike of the year. CPCB monitoring shows 24-hr PM2.5 routinely hitting 300–600 µg/m³ in Delhi on Diwali night.
Delhi Diwali night PM2.5 (2023): 290–570 µg/m³ across monitoring stations (CPCB real-time data).
CPCB real-time monitoring data, Delhi stations [4] · Annual Diwali AQI reports
Meteorological inversion — the trap
In winter, cold air near the ground is trapped under warmer air above (temperature inversion). Pollutants cannot disperse vertically. The same emission load on an inversion day is 3–5× more harmful than a well-mixed day.
Mixing layer height drops from ~1500m (summer) to ~200–400m (winter mornings) in Delhi.
IMD atmospheric sounding data · Deshpande et al. (2021), Atmospheric Environment [5]
Structural year-round sources
Vehicle emissions, road dust, construction, and coal power plants contribute 50–60% of Delhi's baseline PM2.5 throughout the year — even on non-smog days. The seasonal spike is a multiplier on top of a persistently high baseline.
Source apportionment: vehicles + road dust ~28%, industry ~22%, coal power ~15%, residential biomass ~12% (Delhi IIT source apportionment study 2018, cited by EPCA).
IIT Kanpur Source Apportionment Study (EPCA 2018 citation) [6] · CPCB annual report
Section 05 · Policy & Progress
What's being done — and where it's falling short.
India launched the National Clean Air Programme (NCAP) in 2019 — a nationwide plan with city-level targets and funding. The data shows partial progress, but the pace is far from what the health burden demands.
NCAP Target vs Progress (as of 2024)
NCAP revised its target to 40% PM reduction by 2026 (from 2017 baseline). Average across 131 non-attainment cities. Progress figures from MoEFCC / CPCB reporting.
MoEFCC NCAP progress report 2024 · CSE India analysis · Target figures: Ministry of Environment, Forest and Climate Change [7]
Delhi Metro — a proven intervention
Delhi Metro expansion reduced vehicle-kilometres travelled and lowered the city's per-capita transport emissions. World Bank and DMRC estimates credit the metro with preventing 570,000 tonnes of CO₂/yr — demonstrating that infrastructure investment changes behaviour at scale.
DMRC Sustainability Report 2023 · World Bank India Transport project assessment [8]
PM Ujjwala Yojana — LPG for rural households
96M+ LPG connections distributed to Below Poverty Line families as of 2023. Reduces indoor air pollution deaths from cooking with biomass. Sustained usage (refills) remains a challenge — economic constraints limit actual fuel switching.
PIB India — PMUY Progress Report, March 2024 [9]
BS-VI fuel standards
India leapfrogged BS-V directly to BS-VI (Bharat Stage VI) emissions standards in April 2020 — equivalent to Euro 6. This was a significant policy decision that reduced vehicle particulate emissions in compliant new vehicles. CPCB credits this as a major contributor to the modest PM reductions seen since 2020.
CPCB Annual Report 2022–23 · MoRTH notification S.O. 1307(E) [10]
The equity dimension: who suffers most
Air pollution in India is not equally distributed. Those least responsible for emissions — subsistence farmers (who burn stubble because they cannot afford mechanical harvesters), daily-wage outdoor workers, and rural women using biomass cookstoves — bear the highest exposure burden. Meanwhile, wealthier urban households can afford air purifiers, sealed buildings, and reduced outdoor exposure. A 2022 analysis in Nature Sustainability found that the poorest 20% of India's population faces 40% higher PM2.5 exposure than the richest 20%.
Asher et al. (2022). Nature Sustainability, 5, 1201–1209. doi:10.1038/s41893-022-00974-0 [11]
The numbers are not abstract. Every 10 µg/m³ of PM2.5 above the WHO guideline reduces life expectancy by roughly one year. In Uttar Pradesh, where annual PM2.5 averages 90+ µg/m³, that's 8 years — the equivalent of living with uncontrolled type 2 diabetes.
India's air quality problem has technical solutions — cleaner fuels, better vehicle standards, crop residue management, industrial regulation. The gap between current reality and WHO guidelines is not geological or culturally fixed. Countries have closed it within decades. What it requires is consistent political will, enforcement infrastructure, and investment at the scale the death toll demands.
What you can do
Check CPCB's real-time AQI app. Use N95 masks on high-AQI days. Support PM Ujjwala LPG refill subsidies. Advocate for local NCAP enforcement. The data shows change is possible — but only if it's demanded.
References
Sources
All sources are publicly accessible.