Why road dust is emerging as Delhi's biggest pollution threat

📌 Summary:

• Context: A January 2026 report by an expert panel of the Commission for Air Quality Management (CAQM) identified road dust as Delhi's major pollution source — acting as "both a primary emission and a persistent source"
• Road dust covers airborne dust from roads/shoulders, vehicle movement, dry soil, road wear, potholes, broken edges, unpaved stretches, road-tyre-brake wear, and debris from construction & demolition (C&D) material transport
• Mechanism: dust deposited on roads is resuspended by vehicular movement in dry conditions — keeps PM levels elevated even without active dust generation
• Difference from C&D dust: road dust is a line source along corridors (needs corridor-wide management); C&D dust is a point source (needs site-level enforcement)
• Resuspension drivers: continuous dust deposits at road edges/medians, unsuitable infrastructure design, poor maintenance, inadequate dust-management, irrigation hose-pipe spills, encroachments, unauthorised parking
• Local roads and secondary streets often excluded from regular maintenance — leading to "prolonged dust emissions"
• Key data:
  • CSIR-NEERI/CRRI study (Feb 2025): few Delhi stretches recorded PM10 levels of 1700 µg/m³ within 10 m of road — vs CPCB limit of 100 µg/m³ (24-hour) and 60 µg/m³ (annual)
  • IIT-Delhi-led 2023 multi-city study: as tailpipe emissions fall with cleaner fuels, non-exhaust sources (resuspendable road dust, tyre wear, brake wear) gain relative significance
  • Across 32 cities, silt loads ranged from 0.2 g/m² to 111.2 g/m²; Delhi averaged 14.47 g/m²
  • Nationwide, exposure to road dust linked to >10,207 premature deaths annually
  • Aravalli range degradation has weakened the natural dust barrier around Delhi → more wind-blown dust
• Response so far: Mechanical Road Sweeping Machines (MRSMs); MCD deploys 57,000 sanitation workers; PM10 standard 100 µg/m³ (24-hr)

🎯 UPSC Relevance: GS3 Environment — air pollution, EIA-adjacent regulation; GS2 Governance — CAQM, ULB coordination; GS3 Health — PM2.5/PM10 morbidity

📝 Prelims Facts:

• CAQM = Commission for Air Quality Management in the National Capital Region and Adjoining Areas, established 2021 by Act of Parliament
• CPCB PM10 standards: 100 µg/m³ (24-hr), 60 µg/m³ (annual)
• NEERI (National Environmental Engineering Research Institute) and CRRI (Central Road Research Institute) are CSIR labs
• PM (Particulate Matter): PM10 (≤10 microns) and PM2.5 (≤2.5 microns) — finer particles enter bloodstream

🔑 Key Term: Resuspension — Process by which previously deposited dust on road surfaces is lifted back into the air by vehicle-induced turbulence or wind, perpetuating particulate-matter pollution