Causes of Smog in Northern India

New Delhi:(Page3 News Network)-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.
The period being the harvesting season of khalif-2012, the open burning of the biomass residue in the paddy fields of rural Punjab/Haryana, options for taking any steps are limited as this typically happens in the backdrop of unfavorable stable atmospheric conditions that traps SPM in the boundary layer above the ground. Incrementally, diesel operated urban transport also adds to the air pollution that reduces the visibility further. Government is already undertaking possible steps for discouraging diesel run public transport and encouraging utilization of CNG widely part from imposing emission norms (Bharat IV now for new vehicles getting registered).
Increased frequency of respiratory related asthmatic troubles to the vulnerable segment of the society (elderly and children) is the well known impact for which reduced exposure can minimize the adverse effects during the periods of smog.
The above information was given by the Minister for Science & Technology and Earth Sciences, Shri S. Jaipal Reddy to the Parliament.