While the Delhi Government has claimed a fall of 100 points in the most prominent pollutant PM2.5 following the implementation of the odd-even formula, the data of State Government’s agency Delhi Pollution Control Committee’s (DPCC) for the month of December and January show no difference.
While Transport Minister Gopal Rai claimed the PM2.5 level is down by 100-point to 300 ug/m3 in January from 400-465 ug/m3 in December, the DPCC data that was regularly published by The Pioneer shows that the level of PM2.5 was consistently below 300 (often below 250) throughout December, barring a few aberrations. Thus the DPPC data shows there is no change in the PM2.5 level since the odd-even rule came into force.
Claiming on Thursday that pollution caused by vehicles has actually gone down in inner Delhi, Gopal Rai said, “Everyone is saying that the odd-even formula has made Delhi congestion-free, but what about pollutionIJ They are claiming that pollution has not come down but has actually increased. These are all myths based on half facts. People are confusing PM10 with PM2.5 when the former has nothing to do with vehicular pollution. The main cause of PM10 is dust while PM2.5 is caused by vehicular emissions. While there is no significant drop in PM10 levels, PM2.5 has decreased after implementation of the odd-even scheme.”
However, the real-time live pollution data recorded by the mobile meters of DPCC showed that there were no major changes in PM2.5 levels in the first four days of implementation of the odd-even experiment.
According to the report released on Tuesday, the levels of PM2.5 in 17 locations in the city oscillated between 350 to 449 ug/m3 while on Wednesday it was observed at a minimum of 161 and a maximum of 294 at different locations.
DPCC data is based on an average of 24 hours, the data of the last six days shared by Delhi Government is based on a 20-minute timeline.
Significantly, the database of PM2.5 in December, which was regularly derived from the DPCC’s Ambient Air Quality Index (AAQI) showed that mass concentration of PM2.5 oscillated between 129 to 322 (ug/m3) in RK Puram, Mandir Marg and Civil lines stations. The other three stations of DPCC are in Anand Vihar, IGI and Punjabi Bagh.
Also in the same month, the mass concentration never exceeded 381 ug/m3 (Anand Vihar, the area is outer Delhi) in any of the stations. The highest level of concentration in inner Delhi was observed on December 23 which was 327 in Punjbai Bagh. On the same day, the concentration was 276 ug/m3 in RK Puram and 322 ug/m3 in Mandir Marg.
Based on these figures, the average level of PM 2.5 has to be below 300 and cannot be 400 or 465 ug/m3 as claimed by the Government.
Notably in mid-December, the average concentration of PM2.5 in RK Puram, Punjbai Bagh and Mandir Marg was 223, 198 and 210 (ug/m3) respectively. These figures illustrate that concentration of PM2.5 was never measured above 330 ug/m3 for inner Delhi in December 2015.
As per the DPCC, a significant drop in PM2.5 was measured in AAQI after December 20. On December 21, PM2.5 level registered a significant drop and was measured at 190, 120 and168 ug/m3 in RK Puram, Punjbai Bagh and Mandir Marg respectively.
Experts in Delhi have said that drop or rise of primary pollutants in the city is dependent on the weather conditions.
A senior IMD official said that in the last week of December, considerable fall in pollution was observed and the pattern was followed in the first three days of January. “The weather pattern in Delhi is completely different this year. The temperature and wind directions both are responsible for the fluctuations in pollutant size in city air,” said the official.