‘Fire count gives a skewed picture of stubble burning’

Context

  • Govt claims: 92% reduction in fire counts in Punjab and 90% reduction in Haryana (since 2021).

  • New study by iForest questions this, arguing fire counts undercount actual stubble burning.

  • Alternative metric — Burnt Area — shows only ~30% reduction.

  • Highlights risk of policy misinterpretation due to dependence on single-source satellite data.

Key Issue

Fire Counts ≠ Actual Stubble Burning

  • Fire counts = number of active fires detected by satellites.

  • Burnt area = actual land surface that shows evidence of burning.

iForest Findings

  • Burnt area in Punjab + Haryana:

    • 31,500 sq km (2022)19,700 sq km (2025)

    • ≈30% decline, not 90%+.

This mismatch suggests structural under-detection and flawed monitoring.

Why Fire Counts Are Misleading

a) Limited detection by Polar-Orbiting Satellites

India uses data from:

  • MODIS (NASA’s Terra & Aqua)

  • VIIRS (Suomi-NPP)

Limitations

  • Observe India only during fixed time window: 10:30 a.m. – 1:30 p.m.

  • Can detect only active flames at that moment → not 24-hour coverage.

  • Miss small fires and short-duration fires.

  • Seasonal haze or clouds further reduce detection

b) Time-of-Day Bias

  • iForest analysis (using Meteosat SEVIRI):

    • Most stubble fires since 2022 occur in the evenings.

    • This is outside MODIS/VIIRS overpass times.

  • Result → systematic undercounting of fires.


c) Resolution Issues

  • MODIS: 1 km resolution → misses small field fires.

  • VIIRS: 375 m resolution → better but still inadequate for scattered small fires.

What is ‘Burnt Area’? Why is it Better?

Burnt Area = Land surface that shows spectral signature of past burning

—not just active flames.

iForest used:

  • Sentinel-2 (MSI instrument)

    • 100m × 100m resolution

    • Detects burnt residue, char, ash

    • Provides a more comprehensive picture

    • Passes over every 5 days; data available with 8–15 day lag

Despite limitations, it captures:

  • Total area burned

  • Fires missed by active detection sensors

Hence a more robust metric, especially for policy evaluation.

Role of Geostationary Satellites (Meteosat 8 & 9)

Advantages:

  • Continuous monitoring (every 15 minutes)

  • Detects fire timing patterns (e.g., evening peaks)

Limitations:

  • Not suitable for precise fire count

  • Lower spatial resolution → not ideal for small fires

Key Insight from SEVIRI:

  • Majority of post-2022 fires occur after sunset
    not captured by MODIS/VIIRS.

Implications for Air Quality & Policy

a) Undercount = Underestimated Emissions

Missed fires:

  • Lead to underreported PM2.5, NOx, SOx emissions

  • Distort air pollution models for Delhi NCR

  • Affect emergency response & long-term mitigation planning

b) Policy Success May Be Overstated

  • Govt measures (e.g., DSR promotion, ex-situ residue management, Happy Seeder) may appear more successful than they are.

c) Budget & incentive misallocation

Wrong data →
Wrong hotspots →
Ineffective targeting of:

  • Machinery subsidies

  • Enforcement drives

  • Crop residue management funds

Broader Governance Problem

Over-reliance on a single metric

Using fire counts alone → Unidimensional indicator → Risk of data-driven misgovernance

Need for integrated monitoring

Combine:

  • Fire counts (MODIS/VIIRS)

  • Burnt area (Sentinel-2)

  • Temporal monitoring (SEVIRI)

  • Ground surveys

A multi-sensor approach ensures reliability.

Conclusion

  • Fire counts provide a partial and skewed picture.

  • Burnt area estimation, despite lags, gives a truer reflection of ground realities.

  • For effective policy and accurate pollution assessment, India needs:

    • Multi-sensor satellite integration

    • Transparent data sharing

    • Ground-level validation

    • Policy recalibration based on actual burnt area

Leave a Reply

Your email address will not be published. Required fields are marked *