New Delhi, April 6 : The air quality index in the national capital taht had been good since the Lockdown21 was enforced, witnessed a marginal deterioration on Monday, said the Centre run System of Air Quality and Weather Forecasting And Research (SAFAR). It slipped from 'Good' to the 'Satisfactory' category. According to SAFAR, the overall air quality index in Delhi docked at 87 on Monday. The major pollutants PM10 and PM2.5 stood at 87 and 47, respectively. This was after the widespread use of fire crackers by many in the DElhi-NCR during the PM's 9baje9minute activity on Sunday. Despite people being urged to loght candles and diyas, many took to a mini Diwali celebration. "The Covid-19 disease attacks the respiratory system and despite it fire crackers were used unmindfully", many Twitter users rued. The SAFAR stated that the particulate matter 2.5 has witnessed a reduction up to 49 per cent during the ongoing lockdown. "Strong surface winds and a slight increase in suspended dust are forecasted for the next two days. Ozone concentration has increased compared to its normal values and is one of the lead pollutants," said SAFAR. - /IANS