Diwali celebrations spikes Toxicity level up to 26 Times in Delhi.Nov 09, 2018
Safar, a pollution forecasting entity, had warned that the capital city’s pollution level could soar between Wednesday night at 11 and Thursday morning at 3, even if only 50 per cent of the firecrackers as compared to 2017 Diwali were burnt this year.
In the middle of a busy week, Delhi was enjoying a pleasant day with clear sky and few vehicles on the road. But the euphoria lasted till Wednesday 8pm, after which Delhi residents started bursting firecrackers. By midnight, entire Delhi was engulfed by a thick smoke, laced with toxins and chemicals.
Despite the courts banning on firecrackers in the city, this year’s Diwali turned out to be increasingly polluted than last year.
On Thursday at 1am, pollution levels had soared up to 26 times above safety standards. The Union government’s pollution forecasting agency – Safar – had already alerted that Delhi’s level of pollution could soar between the late hours on Wednesday to early hours on Thursday. The warning from the forecasting agency played out in reality.
The data available with the DPCC – Delhi Pollution Control Committee showed that the average concentration of PM2.5 started shooting up from Wednesday 9pm. A senior official from the environment department of Delhi government said: “By 1am, the average concentration of PM2.5, the more harmful particles, had shot up to a peak of 1560 µg/m3. This is nearly 26 times above the daily safe standards.”
Other pollutants such as nitrogen dioxide, PM10 and sulphur dioxide shot up during the four crucial hours. PM10 levels rose to a peak of 1859µg/m3 around 1am, which was 18 times higher than safety measures. Similarly, the levels of SO2 and NO2 crossed their limits of 80µg/m3 per day around 11am when celebrations were at their peak.
Only a handful of vehicles were on the road, pollution forecasting agencies said the contribution from stubble burning regions were also less, around 10 per cent.
A Delhi Pollution Control Committee scientist said: “Wednesday’s pollution primarily came from firecrackers and hence it was the PM2.5 that shot up alarmingly. Had the cause for the pollution spike been natural dust or vehicles, then PM10 levels would have also shot up.”
Stubble burning contributed in overall PM2.5 concentrations during Diwali this year, estimated around 10 per cent by IITM – Indian Institute of Tropical Meteorology in Pune. Safar said the contribution of PM2.5 in PM10 shot up from 50 per cent to 70 per cent on the night of Diwali, mainly due to emissions from crackers.
Worst affected areas:
Locations such as Ashok Vihar, Jahangirpuri, Nehru Nagar, Wazirpur, Punjabi Bagh, Anand Vihar and RK Puram were some of the worst polluted spots. NO2 levels soared to the maximum in Punjabi Bagh, in Ashok Vihar, PM2.5 levels peaked up to 1250µg/m3. While Karni Singh Shooting Range registered the maximum increase in SO2 levels.
Drop in temperature:
Experts said that Delhi and the surrounding areas encountered its coldest night this season which further compounded the problem. The dropping temperature started an inversion and the pollutants got trapped. A senior official said: “While the temperature near the surface dropped to around 10-11 degrees Celsius, the temperature at a height of 500m and above ranged between 19-20 degrees Celsius. This trapped the pollutants as there was an inversion of temperature and they could not disperse.”
Speed of the wind had also plummeted to below 10 km. To disperse pollutants, Delhi would need a minimum wind speed of 10 km an hour, and plenty of ventilation with an index of 6,000m. However, on Thursday, the ventilation index had dipped further to around 3,000 sqm per second.