Summary:
Influence of stubble burning also came down as upper air winds slowed down and changed direction, resulting in a brief respite from pollution. "Rest was made up of emissions from local sources such vehicular combustion. "However, localized weather took over by the evening of November 11. Before pollutants could be flushed, inversion layer (beyond which pollutants cannot escape) fell down from 1600 metres to just 45 metres in eight hours and Delhi entered the severe zone again which delayed full recovery by two days," SAFAR said. "As per SAFAR forecasting model, the pollution contribution of Gulf Dust Storm on peak day (8th Nov 2017) was around 40 per cent and 25 per cent from stubble burning," the report said.Till about November 6, the mean PM2.5 level remained between 140-190 ug/m3, usual for this time of the year, SAFAR, the only agency which puts out pollution forecast bulletins in India, said.Subsequently, from around November 10, there was no pumping of dust from West Asia..