Air Quality

Fine particulate matter (≤2.5µm). Penetrates deep into lungs and bloodstream. Major source: vehicle emissions, industrial combustion, biomass burning. Long-term exposure is linked to respiratory and cardiovascular diseases, reduced lung function, and premature mortality.

PM10

Coarse particulate matter (≤10µm). Inhaled into airways. Sources: dust, construction, road dust. While larger than PM2.5, PM10 can still cause significant respiratory irritation and aggravate conditions like asthma and bronchitis.

NO₂ (Nitrogen Dioxide)

From vehicle exhaust and industrial burning. Irritates lungs and reduces immunity to respiratory infections. High concentrations are common in urban areas with heavy traffic congestion, and prolonged exposure is linked to increased asthma attacks in children.

Ozone (O₃)

Ground-level ozone forms when pollutants react in sunlight. Causes respiratory problems, aggravates asthma. Unlike the protective stratospheric ozone layer, ground-level ozone is a harmful pollutant that peaks during hot summer afternoons in urban areas.

India AQI Trend Context

According to CPCB 2024 data, 132 Indian cities exceeded the National Ambient Air Quality Standards for PM2.5. Delhi, Kolkata, and Mumbai consistently rank among the most polluted cities globally during winter months when temperature inversions trap pollutants near the surface. The National Clean Air Programme (NCAP) targets a 40% reduction in PM2.5 by 2026 relative to 2017 levels across 131 non-attainment cities, but progress has been uneven — while Indore and Ahmedabad have met early milestones, Delhi and Kolkata continue to lag significantly.

Health Impact by AQI Category

Good (0-50)

Minimal impact. Air quality is satisfactory and poses little or no health risk. Outdoor activities can be performed normally.

Moderate (51-100)

Acceptable for most, but sensitive groups should limit prolonged outdoor exposure. Children, elderly, and those with respiratory conditions may experience mild effects.

Poor (101-200)

Breathing discomfort for most people on prolonged exposure. Sensitive groups may experience more serious effects. Reduce outdoor activity.

Hazardous (201+)

Serious respiratory effects. Avoid outdoor activity. Health emergency conditions — everyone may experience more serious health effects. Wear protective masks if going out.

AQI data compiled from CPCB monitoring stations. Pollutant health guidance based on WHO Air Quality Guidelines and CPCB standards. NCAP progress data from MoEFCC annual reviews.