WHY PM2.5, NOT PM10, NEEDS URGENT ATTENTION

NEWS – With the onset of winter, Delhi’s air quality has once again worsened, with AQI touching the ‘poor’ category (294). While governments announce measures such as EV adoption and new studies, experts argue that India’s air pollution response remains misdirected—overemphasising PM10 while neglecting the more lethal PM2.5.

UNDERSTANDING PARTICULATE MATTER

• PM10: Particles ≤10 micrometres; lodge in upper respiratory tract.
• PM2.5: Particles ≤2.5 micrometres (≈1/20th of a human hair); penetrate deep into lungs and bloodstream, affecting vital organs.
• Why PM2.5 matters more: Higher toxicity, stronger links to cardiovascular diseases, strokes, asthma, and premature mortality.

AQI AND POLLUTANTS MEASURED

India’s AQI tracks PM10, PM2.5, NO₂, SO₂, O₃, CO and NH₃, categorised into six levels from Good to Severe. However, public discomfort even on “better” AQI days reflects the disproportionate harm caused by PM2.5.

SOURCES OF AIR POLLUTION IN DELHI

• Vehicular emissions and road dust
• Industrial emissions and coal-based power plants
• Construction activity
• Biomass burning and stubble burning
• Unfavourable geography of the Indo-Gangetic Plains, trapping pollutants

POLICY GAPS IN INDIA’S APPROACH

• NCAP focus: Targets only PM10 reduction (40% by 2026), sidelining PM2.5.
• Misplaced actions: Smog guns and short-term measures lack scientific backing.
• Weak regulation: Severe understaffing in CPCB and SPCBs despite rising industrial output.

GLOBAL LESSONS

A recent SFC report shows how countries like China, Mexico and Poland tackled pollution through:

• Clear political leadership (e.g., Beijing’s “war on pollution”)
• Science- and health-based standards (Mexico City’s ProAire)
• Airshed-based planning and industrial relocation

WAY FORWARD

• Prioritise PM2.5-centric standards and targets
• Strengthen pollution control institutions and manpower
• Adopt airshed-based, inter-state coordination
• Improve risk communication linking air quality to health and economic losses

CONCLUSION: India’s clean air mission will remain incomplete unless PM2.5 becomes the central pillar of air pollution policy.