POLLUTION: Causes of Smog in Northern India

New Delhi, November 27, 2012: As per scientific analysis, the recent "Extreme Pollution Episode" lasted for 12 days (October 26 -November 8, 2012) was due to short range transport of smoke from Punjab /Haryana as indicated by satellite imagery which got directed towards Delhi region due to favourable northerly winds as determined from back trajectory analysis and air quality forecasting model.

Local meteorological conditions in and around Delhi were highly stable that prevents the dispersion of suspended particulate matter (SPM) viz. smoke particles in this case. Once supportive wind regime changed, the pollution came back to pre-episode level. It was hence caused by a mix of man-made activities associated with field level biomass burning supported by a favourable upwind natural phenomenon.