During the period 2018-2025, Delhi witnessed its lowest average PM10 and PM2.5 concentration levels in the current year, barring COVID year 2020.

1. At a Glance

2. Why in the News

3. Background & Evolution

4. Core Static Facts

5. Multi-Dimensional Analysis

Environmental - Particulate matter (PM10 = ≤10 µm; PM2.5 = ≤2.5 µm) — primary winter pollutants in Delhi from vehicles, biomass, construction dust and stubble burning [S2]. - CAQM's 27th meeting identified PM2.5 as the key pollutant in Delhi based on Supreme Court-mandated expert report [S6]. - Despite improvement, 2025 levels remain far above WHO guidelines (PM2.5 annual = 5 µg/m³) (WHO Global Air Quality Guidelines, 2021).

Legal / Constitutional - CAQM is a statutory body under a Central Act; supersedes earlier SC-created EPCA — exemplifies legislature reclaiming environmental governance from judicial creations. - Its orders are binding on State Governments of Punjab, Haryana, UP, Rajasthan and GNCTD [S2]. - Linked to Article 21 (right to clean air, M.C. Mehta v. Union of India) and Article 48A / 51A(g) (DPSP and Fundamental Duty).

Administrative / Federal - Air-shed approach overrides state boundaries — a rare cooperative federal mechanism for an inter-state externality (stubble burning, transport). - Enforcement Task Force (ETF) + Flying Squads monitor compliance [S2]. - Bottlenecks: stubble burning in Punjab, weak SPCB capacity, NCR construction enforcement gaps.

Scientific / Technological - Revised GRAP is AQI-trigger based: Stage I (Poor 201–300), II (Very Poor 301–400), III (Severe 401–450), IV (Severe+ >450) — CPCB framework cited by CAQM [S5]. - Push toward CNG, BS-VI fuels, EVs, PNG in industry, anti-smog guns, mechanised road sweeping under sectoral plans [S2].

6. Recent Developments (last 12-18 months)

7. Prelims Hooks

8. Mains Relevance

9. Related Topics to Study Next

10. Common Errors / Trap Areas

11. Sources