Air Quality & Pollution Forecast — India

What's on the Map

• PM2.5 — fine particulate matter (µg/m³), the primary health-relevant pollutant metric used by AQI systems worldwide.
• PM10 — coarse particulate matter (µg/m³), including dust and larger combustion particles.
• AOD 550nm — total column aerosol optical depth at the 550 nanometre band, a unitless measure of how much aerosol is scattering or absorbing light through the full atmospheric column.
• Dust AOD 550nm — the dust-specific component of AOD, isolating mineral dust transport (e.g. pre-monsoon dust storms over northwest India) from smoke, sulphate and other aerosol types.
• Visibility (IGP / AOD-based) and Visibility (PM / Koschmeider) — two independent visibility estimates in metres, described below.

How Visibility Is Estimated

VayuMet runs two independent, experimental formulas to translate aerosol loading into a visibility estimate, both incorporating a per-pixel humidity correction f(RH) derived from GFS 2 m temperature and dew point:

• AOD-based IGP formula: V = 4 × H_eff / (AOD × f(RH)) — integrates column AOD over an effective mixing height (default 1,000 m).
• PM2.5 Koschmeider formula: derives visibility from near-surface PM2.5 concentration and the same humidity correction.

Both methods are experimental and intended for spatial pattern guidance (e.g. identifying haze corridors along the Indo-Gangetic Plain), not as a substitute for official METAR/TAF visibility reports — use the Aviation Dashboard for operational aviation visibility.

Questions This Page Answers

• Is the haze over my city mainly dust or combustion smoke?
• Will fine particulate levels build up overnight under a winter inversion?
• Which corridors along the Indo-Gangetic Plain are likely to see visibility fall?

How to Read It

• Dust or smoke? High PM10 with high Dust AOD points to mineral dust; high PM2.5 with low Dust AOD points to combustion smoke. They clear differently and call for different responses.
• Compare with the national standard. India's 24-hour National Ambient Air Quality Standards are 60 µg/m³ for PM2.5 and 100 µg/m³ for PM10.
• Expect the worst hours at night and early morning, when a shallow mixing layer traps pollution near the ground; afternoon mixing usually brings some relief.
• Visibility layers are experimental estimates, not observations — check airport visibility reports before acting on them.

Go Deeper

• Forecasting India's smog season — why one air quality number cannot tell you what you are breathing.
• District weather warnings — the fog hazard class, active in winter.
• Aviation dashboard — observed airport visibility (METAR) to cross-check the estimates.

Data Source

Who Uses This

Air quality and visibility maps support flight planning where haze or dust reduces visibility below VFR minimums, public health advisories during high-pollution episodes (e.g. winter inversion events over the Indo-Gangetic Plain), and event or logistics planning around dust storms and smoke transport.