Subject: Environment & Ecology

The World Health Organization (WHO) released revised Global Air Quality Guidelines (AQGs) in 2021, marking a significant shift towards stricter air quality standards to protect public health and environment.

Key Points of Revised WHO AQGs 2021

• Stringent Pollutant Limits: The guidelines recommend annual mean concentrations for PM2.5 not exceeding 5 µg/m³ and NO2 not exceeding 10 µg/m³.

• Comprehensive Coverage: The guidelines cover six major air pollutants:

  • Particulate Matter (PM2.5 and PM10).
  • Ground-level Ozone (peak season mean 8-hour concentration ≤ 60 µg/m³).
  • Nitrogen Dioxide.
  • Sulfur Dioxide.
  • Carbon Monoxide.

Differences from 2005 Guidelines

• Stricter Standards: Significant reduction in recommended limits:

  • PM2.5: From 10 µg/m³ to 5 µg/m³.
  • PM10: From 20 µg/m³ to 15 µg/m³.
  • NO2: From 40 µg/m³ to 10 µg/m³.

• New Additions: Introduction of new limits for ozone and carbon monoxide.

Required Changes in National Clean Air Programme (NCAP)

• Infrastructure Enhancement:

  • Expedite installation of Flue Gas Desulphurization (FGD) systems in thermal power plants.
  • Review and potentially revise extended deadlines for SO₂ compliance (2027-2029).

• Implementation Reforms:

  • Develop standardized operating procedures across states.
  • Strengthen monitoring of PM2.5 instead of focusing solely on PM10.
  • Improve fund utilization mechanisms in cities.

• Policy Adjustments:

  • Align national standards with WHO guidelines progressively.
  • Enhance inter-state coordination for better implementation.

India's commitment to achieving the revised WHO standards requires a multi-pronged approach combining technological interventions, policy reforms, and stakeholder engagement. Success stories like Delhi's switch to CNG and Indore's clean air initiatives demonstrate the feasibility of achieving ambitious air quality targets through determined action.