The AQI we Choose

The air quality in northern India, particularly New Delhi, has deteriorated significantly in recent weeks, with pollution levels reaching record-breaking "severe-plus" readings. This comes despite a relatively mild start to the season. The sudden spike in particulate matter (PM2.5) levels and the resulting air stagnation have sparked renewed discussions about air pollution and the need for long-term, scientifically based solutions. The issue has garnered attention amid the ongoing COP29 summit in Baku, where experts emphasize moving away from fossil fuels to curb pollution and its impact on public health.

Contributing Factors and Scientific Insights

• Weather Conditions and External Pollution Sources: The increase in pollution levels can be attributed to a combination of unfavorable weather conditions, such as low wind speeds and atmospheric stagnation, and an intrusion of pollutants from regions like Punjab and Haryana. Despite a significant reduction in stubble-burning incidents, the intrusion of toxic air from higher altitudes exacerbates the pollution situation in Delhi.
• Role of Vertical Pollution Layers: Models suggest that a thick pollution layer at around 500m altitude, coupled with lower temperatures at night, has contributed to worsening air quality. This vertical air mass descends during the night, leading to a buildup of particulate matter. As the boundary layer rises during the day, pollution levels decrease, but local emissions and external sources continue to affect air quality.
• Unpredictable Weather Patterns and La Niña: The unusual climate events, including a record-warm October and delayed onset of La Niña, have affected wind patterns and air circulation, making it difficult to predict and mitigate air pollution. La Niña, which typically helps with better winter circulation, has not yet fully set in, contributing to the air stagnation that worsens winter pollution.

Data, Challenges, and Policy Implications

• Discrepancy in AQI Readings: A significant issue highlighted is the discrepancy in air quality readings between private agencies and official sources. While some private agencies report AQI values exceeding 1,000-1,500, the official readings are capped at 500, raising doubts about the accuracy of the AQI system. This discrepancy arises due to India's own AQI breakpoint system, which uses different thresholds compared to the WHO guidelines, leading to confusion about the actual severity of pollution.
• Satellite Data Limitations and Stubble Burning: The shift in the timing of stubble burning in north-west India, allegedly to evade detection by satellite-based monitoring systems, has raised concerns about data accuracy. NASA satellites are currently used to track these activities, but they only pass over the region twice daily. There is a need to enhance the capacity to use Indian geostationary satellites (INSAT-3D/3DR) for more frequent and accurate monitoring, ensuring independence from foreign data sources.
• Need for Integrated Air Quality and Climate Strategy: Addressing the air pollution crisis requires an integrated strategy that combines air quality management and climate action. A scientific resource framework is necessary to address the problem comprehensively, as discussed in recent stakeholder meetings. The focus must be on health-centric measures, leveraging technological advances and fostering inter-sectoral cooperation to combat pollution effectively.

Practice Question:

Critically analyze the challenges in managing air pollution in India, with a focus on the discrepancies in air quality monitoring, the role of satellite data, and the need for integrated climate strategies. Suggest ways to address these issues for better air quality management.