Unlike previous years, stubble burning has taken some time to set in its impact on the atmosphere of the National Capital Region (NCR) this year. Due to a spike in field fires and favourable conditions for the transfer of emissions to Delhi-NCR, the percentage of stubble burning in Delhi's PM2.5 pollution increased to 26% on Sunday, the highest level this year.
Farm fires were responsible for 21% of the PM2.5 pollution in the nation's capital on Saturday.
PM2.5 are tiny particles with a diameter of 2.5 microns or less that can penetrate the respiratory system deeply, make it to the lungs, and then enter the bloodstream.
Due to a protracted period of rain in early October and slow transport-level winds that were not strong enough to bring smoke from agricultural fires to the national capital, stubble burning's impact to Delhi's PM2.5 pollution remained modest (up to 7%) until Friday.
Stubble burning on Diwali (24 October) added 5-8% to Delhi's overall PM2.5 pollution. Farm fires contributed 25% to the PM2.5 pollution in Delhi on Diwali in 2021, 32% in 2020, and 19% in 2019.
Punjab experienced 1,761 farm fires on Sunday, 1,898 on Saturday, 2,067 — the most thus far this season — on Friday, and 1,111 on Thursday, according to the Indian Agricultural Research Institute (IARI). On Sunday, there were 112 and 43 incidences of stubble burning, respectively, in Haryana and Uttar Pradesh.
The Commission for Air Quality Management had on Thursday said the increased incidents of stubble burning in Punjab this year "is a matter of serious concern".
Only around 39% of the Punjab's agricultural land had been harvested as of 24 October according to satellite remote sensing data, making the increasing frequency of fire incidents frightening, it said.
Paddy straw burning in neighboring states is a significant factor in the alarming increase in air pollution levels in the national capital in October and November, which also coincides with unfavorable climatic circumstances.
Before producing wheat and vegetables, farmers swiftly remove crop leftovers from their fields by setting them on fire.
Punjab reported 71,304 farm fires between 15 September and 30 November of last year and 83,002 agricultural fires during the same time period in 2020, according to the Indian Agricultural Research Institute.
The proportion of farm fires in Delhi's PM 2.5 pollution reached at 48% on November 7 of last year.
Delhi's air quality was in the 'very poor' category on Sunday and deteriorated to the 'severe category' in some areas, with forecasters saying that slow wind speed and an increase in stubble burning, especially in Punjab, may make it worse.
At 9 am, Delhi's overall air quality index (AQI) was 367; by 4 pm, it had improved to 352.
On Saturday, the AQI was 397, the lowest it had been since January. On Thursday, it was 354, on Wednesday, 271, on Tuesday, and on Monday, it was 302. (Diwali).
Anand Vihar (AQI 449) and Vivek Vihar were the two most polluted areas in the capital on Sunday (402).
Environment Minister Gopal Rai said Anand Vihar and Vivek Vihar have been reporting high pollution levels continuously which could be due to construction work related to Regional Rapid Transit System (RRTS).
Rai on Sunday said the Delhi government has set up 586 teams to ensure strict implementation of the ban on construction and demolition activities in the capital in view of worsening air quality.
Graded Response Action Plan (GRAP) is a set of anti-air pollution measures followed in the capital and its vicinity according to the severity of the situation.
It classifies the air quality in the Delhi-NCR under four different stages: Stage I - 'Poor' (AQI 201-300); Stage II - 'Very Poor' (AQI 301-400); Stage III - 'Severe' (AQI 401-450); and Stage IV - 'Severe Plus' (AQI >450).
Stage III calls for the stringent enforcement of a ban on construction and demolition activity in the NCR, with the exception of necessary projects and non-polluting work like plumbing, carpentry, interior design, and electrical work.
Projects involving, among others, national security, defence, railroads, and metro rail will not be subject to the construction moratorium. It may, however, have an impact on housing developments in Noida, Ghaziabad, Gurugram, and other places. There will be no mining permitted in the area.
The next stage in the "Severe Plus" category, or Stage IV, will entail actions such as a ban on trucks entering Delhi, allowing 50% of employees in public, municipal, and private offices to work from home, closing educational institutions, and operating vehicles on an odd-even schedule, among other things.
(With inputs from PTI)
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