‘Fire count gives a skewed picture of stubble burning’, Pg14

Key Highlights:

• The Environment Ministry claimed a 92% and 90% fall in fire counts in Punjab and Haryana respectively since 2021, indicating reduced stubble burning.
• An iForest study using different satellite data estimates a more gradual reduction in burnt area, about 30%, from 31,500 sq. km in 2022 to 19,700 sq. km in 2025.
• Official estimates rely on data from CREAMS using NASA's MODIS and VIIRS on Suomi-NPP satellites, which capture active fires at fixed times.
• iForest suggests using satellite sensors to detect smoke for a better representation of the land burned, as small fires are often missed.

Detailed Insights:

• Current official estimates of stubble burning rely on polar-orbiting satellites that observe India at fixed times, leading to monitoring gaps.
• iForest's analysis used data from the Multi-Spectral Instrument of the Sentinel satellite to calculate burnt area at a resolution of 100m x 100m.
• Meteosat 8 and 9, a geostationary satellite, showed that most fires occur in the evenings, outside the detection time of polar satellites, leading to undercounting.
• Underestimated emissions and mischaracterization of particulate matter loads result from fires missed by polar-satellite sensors, affecting air-quality simulations.
• Government reliance on fire counts as a proxy for gauging decline in stubble burning may be misleading due to satellite limitations.
• True number of fires in the state has been undercounted because polar satellites are unable to compute the actual number of fires over a 24-hour period.

Scientific/Technical Concepts Involved:

• Polar-orbiting satellite: A satellite that orbits the Earth from pole to pole, passing over different locations at different times.
• Geostationary satellite: A satellite that orbits the Earth above the equator and remains in the same position relative to the Earth's surface.
• Burnt area: The actual land area affected by fire, often measured in square kilometers, providing a direct assessment of fire impact.