Delhi's December 2015 Smog Crisis: Severe Air Quality and Winter Biomass Burning

On December 23, 2015, New Delhi recorded its most severe air pollution levels of the year, with ambient concentrations of PM 2.5 and PM 10 escalating dramatically into the hazardous category across the National Capital Region.

Alarming Particulate Concentrations

Data from the System of Air Quality and Weather Forecasting and Research (SAFAR) revealed city-wide averages of 295 micrograms per cubic metre for PM 2.5 and 470 for PM 10 — vastly exceeding national safe thresholds of 60 and 100 µg/m³. Monitoring stations in Anand Vihar recorded peak PM 2.5 values exceeding 400 µg/m³.

Meteorological and Regional Triggers

SAFAR researchers attributed the acute spike to a combination of atmospheric temperature inversions and pollutant transport across the Indo-Gangetic Plains, exacerbated by local biomass burning for winter heating. The December 2015 pollution event served as a major catalyst for emergency public health interventions, including odd-even vehicle rationing trials in early 2016.