New Delhi, Nov 30 (PTI) Unfavourable meteorological conditions and peak of paddy harvesting activity during Diwali led to the deterioration of air quality in Delhi in November, the Commission for Air Quality Management said on Thursday.
According to its data, the November month average AQI was observed at 373 this year, while it was 380 in 2021 and 374 in 2016. There were nine days in the month when the air quality was in “severe” category. It was “very poor” for 17 days and “poor” for four days.
However, the situation could have been worst had the national capital not witnessed rains on some days of the month.
The air quality levels are greatly impacted by the levels of rainfall/precipitation, direction of wind and its speed, which are prime facilitators for dispersal of the pollutants/emissions, it said.
The average wind speed over Delhi and out of the city during November was also relatively slower for long spells with an average speed of only about four kilometres per hour. An average wind speed of at least 10 kilometres per hour and above is desirable for effective dispersion of pollutants, the CAQM said in a statement.
Low-speed north-westerly winds flowing in to Delhi were however observed during the month, leading to pollutant in-flow from such areas. Paddy sowing was disturbed and delayed in many parts of Punjab and Haryana owing to incessant rains which also resulted in delayed harvesting in such areas, it said.
The statement also said that paddy farm fires emanating from Punjab and Haryana, while being much lower than in the last three years, contributed significantly to the PM2.5 load in Delhi-NCR owing to highly unfavourable climatic and meteorological conditions.
“The peak of the paddy harvesting activity in Punjab/Haryana coincided with the festival of Diwali this year, further aggravating the air pollution scenario in Delhi/NCR,” it stated.
“All the factors listed above led to a higher daily average AQI of about 372 as against 320 for 2022. Similar meteorological and climatic conditions also prevailed in November 2021 wherein the daily average AQI was recorded as 377,” it said.
Despite the above scenario, the daily average air quality in Delhi for the 11-month period between January to November this year registered its best index as compared to the corresponding period during the last six years, barring the Covid-affected 2020, the CAQM stated.
The daily average AQI for Delhi during the above noted period in 2023 has been recorded as 190 against 199 in 2022, 196 in 2021, 172 in 2020, 203 in 2019 and 213 in 2018 respectively, it stated.
An AQI between zero and 50 is considered ‘good’, 51 and 100 ‘satisfactory’, 101 and 200 ‘moderate’, 201 and 300 ‘poor’, 301 and 400 ‘very poor’, and 401 and 500 ‘severe’.
This period in 2023 has also witnessed a reduction in daily average PM2.5 and PM10 concentrations as against the last six years.
It recorded a daily average PM2.5 concentration of about 88 µgm/m3 as against ranging from 90-105µgm/m3 during the corresponding periods from 2018 to 2022 (barring the Covid-affected 2020), the statement said.
Likewise, the daily average PM10 concentration in Delhi has been about 192 µgm/m3, which is much lower than a range of 200-230 µgm/m3 during the corresponding periods from 2018 to 2022 (barring the Covid-affected 2020), it said.
The government had invoked GRAP Stage-III on November 2 and GRAP Stage-IV on November 5. Both the stages were later revoked. PTI NIT SMN
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Source: The Print
