As a vast swathe of the North Indian plains gasp for breath and the search for a solution to the air quality problem is lost in the fog of allegations and fingerpointing by rival political parties, much of the blame has come to be placed on Punjab and the stubble-burning in the fields ahead of the rabi sowing season.
This is the dominant accusation in the noisy and influential narrative emerging from the national capital in particular, amplified by the government of Delhi and voices in the media.
Experts have, however, repeatedly underlined that the health emergency in the region is owed only in part to the actions of farmers in Punjab and Haryana — and is in fact, the product of a complex mix that includes, apart from stubble-burning, meteorological and atmospheric factors, road and construction dust, and automobile emissions, etc.
Here are some key questions that put the situation in perspective.
As Delhi sees what is among the most polluted days in recent memory, how does the air quality compare with that in Punjab?
As of noon on November 3, the average AQI of Delhi was 486, while that of the other NCR towns was as bad or worse: Faridabad 484; Ghaziabad 481; Gurgaon 464; Noida 490; and Greater Noida 472, all in the ‘Severe’ range, according to Central Pollution Control Board (CPCB) figures.
The CPCB’s figures as of 4 pm on November 2 (average of the previous 24 hours) for these cities was somewhat better, though still very bad: Delhi 399 (Very Poor); Faridabad 404 (Severe); Ghaziabad 453 (Severe); Gurgaon 364 (Very Poor); Noida 432 (Severe); Greater Noida 438 (Severe).
In comparison, the AQI situation in major cities of Punjab as of noon on November 3, according to the CPCB was as follows: Amritsar 253 (Poor); Bathinda 278 (Poor); Chandigarh 238 (Poor); Jalandhar 327 (Very Poor); Ludhiana 323 (Very Poor); Patiala 377 (Very Poor).
And the corresponding figures for 4 pm on November 2 (average of the previous 24 hours) were: Amritsar 265 (Poor); Bathinda 308 (Very Poor); Chandigarh 279 (Poor); Jalandhar 283 (Poor); Ludhiana 305 (Very Poor); Patiala 263 (Poor)
What were the total number of recorded stubble burning cases until November 2 in Punjab?
Until November 2, a total 22,458 field fires had been recorded in Punjab, including four fires on Saturday (November 2). The highest number of fire incidents on a single day this season was 3,135, recorded on October 31.
Haryana, where 13 cities recorded ‘Severe’ AQI on Friday, has seen far fewer stubble fires — just a fifth of the number recorded in Punjab. Haryana had recorded 4,288 stubble fire this season until October 31.
So, is the polluted air blowing from Punjab to Delhi and beyond in the Indo-Gangetic plains?
Broadly, yes. Punjab is located in the northwest of the country; Haryana lies to the south and southeast of Punjab. Delhi is to the east of Haryana, and to the southeast of Punjab. At this time of the year, winds over Punjab generally blow from the north to the west — it follows that Haryana and Delhi are getting winds from Punjab, which is to their northwest.
But there is an important point to note about the height and speed of the winds.
“Currently winds in Punjab are blowing in the north-westerly direction. These are ‘calm winds’, blowing at speeds less than 2 km per hour, for the past many days. At several places, there is ‘air locking’ too,” Dr Surinder Paul, Director of India Meteorological Department (IMD), Chandigarh, said. Dr Paul said that due to the slow speed of winds, not much pollution from Punjab was going towards Haryana and Delhi.
Experts in the Met department said that the nearly static winds above Punjab are blowing 1-2 km above the surface; it is generally the winds closer to the surface, blowing at heights of 10-15 metres, that are the most effective in carrying polluted air from one place to another.
What then is the role played by Punjab in Delhi’s pollution?
Punjab alone cannot be blamed for Delhi’s pollution, Dr Paul said. It is just that paddy stubble is burned in Punjab and Haryana at the onset of the winter season, when there is a rise in the moisture in the air, wind speed is very slow or calm, and the height of the boundary layer is less.
The smoke from stubble, and industrial and vehicular pollution further add to the air locking, which can be broken either by rain or by fast winds, Dr Paul said, adding that the absence of rain or fast winds leads to the accumulation of pollutants in the air.