As Punjab gets attention, data suggests Haryana, UP contribute to over a third of Delhi’s PM 2.5

Punjab takes the heat for Delhi’s foul air. But the headlines often miss Haryana and Uttar Pradesh, which contribute significantly to the toxic mix.

A total of 19 cities in the National Capital Region appear to have contributed to more than one-third of the PM 2.5 load in Delhi, suggests Newslaundry’s analysis of two weeks’ data compiled by an institute under the Ministry of Earth Sciences. Of these, 11 cities are in Haryana, six in Uttar Pradesh and two in Rajasthan.

Newslaundry’s analysis from October 5 to 19 is based on regional and sectoral contributors forecast by Indian Institute of Tropical Meteorology (IITM), Pune under MoES. This data was analysed before the peak observed on Diwali.

Data suggests that the contribution of local factors such as transport, industry, energy, waste burning etc was 35.4 percent between October 5 and 19. Among these, the share of the transport sector was the highest at 18.32 percent.

The third highest contributor was a curious sector called “others” at 27.65 percent. It’s not clear what emission sources are included in the “others” category. 

Since 2021, IITM-Pune has been predicting PM2.5 load of Delhi with the help of the Decision Support System. It also releases air quality index forecast through the Air Quality Early Warning System (AQEWS), which enables the Commission for Air Quality Management to take pre-emptive measures. Based on mathematical modeling, DSS estimates the contribution of emissions from local sectors in Delhi, 19 districts in three neighbouring states, and biomass burning.

The 19 cities contributing to Delhi’s air pollution are part of the National Capital Region, a vast metropolitan area comprising Delhi and several adjoining districts across Haryana, Uttar Pradesh, and Rajasthan. Given the transboundary nature of air pollution, these cities are integral to regional anti-pollution initiatives and plans such as the Graded Response Action Plan (GRAP) and other Commission for Air Quality Management (CAQM)-led measures.

Regional contributors

In the period analysed, 19 cities contributed 34.52 percent to Delhi’s PM 2.5 load, including 11 in Haryana.

Among the three neighbouring states, Haryana’s average predicted PM 2.5 load to Delhi was the highest at 24.7 percent. The Haryana cities analysed by DSS are Karnal, Faridabad, Mahendargarh, Jhajjar, Rohtak, Sonipat, Panipat, Gurgaon, Rewari, Bhiwani and Jind.

Among them, Sonipat’s average share was the highest at 5.71 percent, followed by Jhajjar at 5.62 percent. For two days (October 5 and 13), Jhajjar was responsible for almost one-tenth of Delhi’s PM 2.5 load. Sonipat saw its highest contribution on October 11 and 12 when its share was 11 percent and 9.3 percent, respectively.

Experts attributed Haryana’s contribution to winds carrying pollutants flowing from its cities towards Delhi. 

Anumita Roy Chowdhury, executive director at Centre for Science and Environment, said: “The transboundary flow of pollution is determined by the direction of the wind. Delhi is on the downwind side of Haryana.” Referring to a source-apportionment study, she said Delhi’s contribution to Noida’s pollution can go up to 40 percent because the wind flow is from Delhi to Noida. On Jhajjar and Sonipat being the key contributors, she said they have industrial areas and thermal power plants.

Uttar Pradesh’s average contribution in the two-week period was 8.4 percent with Gautam Buddh Nagar’s share at 3.05 percent and Ghaziabad at 2.53 percent. The other four districts part of DSS predictions are Meerut, Bulandshahr, Baghpat and Muzaffarnagar.

The share of Rajasthan, which has Alwar and Bharatpur among the 19 cities, was the lowest at 1.39 percent. 

Local factors

Beyond regional factors, DSS examines local factors too and broadly has eight major sectoral contributors:  transport, residential, industries, waste burning, construction, road dust, energy, and other sectors (which include the emissions from the sectors like crematoria, airports, restaurants, non-energy solvent use, and diesel generator sets).

The transport sector’s predicted average share in Delhi’s PM2.5 load was 18.34 percent. It reached its peak on two days at 19.9 percent each on October 13 and 14. The next key contributor was “residential” – which includes wood burning – at 4.75 percent. The share of industries was 3.81 percent and for construction, it stood at 2.55 percent. For the rest of the sectors, it was between 1 percent and 2 percent.

Stubble burning likely to contribute more

The average contribution of stubble burning was 1.21 percent. 

From October 5 to 16, its share remained between 0 to 1.3 percent. It subsequently inched upwards: 2.8 percent on October 17, 4.3 percent on October 18 and 4.6 percent on October 19.

Gufran Beig, chair professor at National Institute of Advanced Studies at Indian Institute of Science, said stubble burning’s contribution is less as of now because the harvest season has been delayed due to floods in Punjab. He said that the coming days would be challenging as in a narrow window, stubble needs to be cleaned up for the Rabi crop. Hence, in all possibilities, the per day burning load would be much higher and so the share of stubble burning is likely to go up as wind trajectory is likely to be favourable for transport, he said.

After regional and local contributors, the biggest contributor to Delhi’s PM2.5 burden was a sector called: “Others”. This segment’s average share was 27.65 percent. In the October 5-19 period, it hit a peak on October 10 when its share in Delhi’s PM 2.5 was 41.2 percent.

An expert, who did not wish to be named, said secrecy shrouds the “others” category. “If it’s not clear what emission sources are part of the ‘others’ category, which contributes to almost one-third to Delhi’s air pollution, it will become difficult for the executive to take informed decisions and mitigation measures. After all, the whole point of DSS was to make CAQM aware of pollution sources in Delhi,” they said.

IITM-Pune scientist Sachin M Ghude, who leads the AQEWS and DSS team, was not immediately available for comment.

With research inputs from Saurabh Shukla.

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