Q. Describe the key points of the revised Global Air Quality Guidelines (AQGs) recently released by the World Health Organisation (WHO). How are these different from its last update in 2005? What changes in India’s National Clean Air Programme are required to achieve these revised standards ?

Model Answer:

In 2021, the WHO updated its Global Air Quality Guidelines (AQGs) after 15 years, setting much stricter threshold limits for six classic pollutants to mitigate severe public health risks.

1. Key Points & Differences (2021 AQGs vs 2005)

• Stricter PM Limits: The annual PM2.5 threshold is slashed by half (10 µg/m³ in 2005 to 5 µg/m³) and PM10 is tightened (20 µg/m³ to 15 µg/m³).
• Drastic NO2 Reduction: The annual Nitrogen Dioxide limit is reduced by 75% (40 µg/m³ in 2005 to 10 µg/m³).
• New Inclusions: Introduces new “good practice statements” for managing highly toxic ultra-fine particles (UFPs) and black carbon.
• Advisory Nature: Remains an evidence-based tool for policymakers, not a legally binding treaty.

2. Required Changes in India’s NCAP

• Align National Standards: Revise India’s outdated 2009 National Ambient Air Quality Standards (current PM2.5 limit is a lenient 40 µg/m³) to approach WHO interim targets.
• Absolute Health Targets: Upgrade NCAP’s percentage-based reduction goals (40% reduction by 2026) to absolute, health-based pollutant concentration targets.
• Airshed Management: Shift governance from isolated, city-specific action plans (131 non-attainment cities) to a broader regional “airshed” approach.
• Multi-Pollutant Focus: Expand NCAP’s monitoring mechanisms (via PRANA portal) to aggressively track NO2, Ozone, and ultra-fine particles alongside PM.

Aligning NCAP with WHO’s stringent AQGs demands a legally backed, airshed-centric governance model to effectively combat pollution, safeguard public health, and ensure environmental justice.