Delhi's air quality in moderate category, likely to deteriorate in 2 days

Air quality in the national capital was recorded in the moderate category on Thursday but is likely to deteriorate in the next two days with a rise in farm fire incidents in Punjab and Haryana.

A total of 407 farm fires were recorded on Thursday in the neighbouring states of Punjab, Haryana, Uttar Pradesh, Rajasthan and Madhya Pradesh with 229 such fires detected in Punjab alone, showed data from the Indian Agricultural Research Institute (IARI).

Haryana recorded 98 fires and Uttar Pradesh recorded 68 such incidents on Thursday.

On the previous day, 272 fires were detected in these five states collectively.

Ministry of Earth Sciences' forecast body SAFAR said that Delhi's air quality index (AQI) is in the moderate category with PM10 as the main pollutant.

"Under dry conditions, local dust gets re-suspended leading to high PM10, in addition to meso-scale transport of dust from desert regions," it said.

According to the Decision Support System (DSS) developed by Indian Institute of Tropical Meteorology-Pune, the ventilation index and the wind speed in the national capital will be lower than average in the next two days, which is unfavourable for dispersion of pollutants.

However, the air quality is likely to improve owing to the rainfall activities on October 17 and 18, which is favourable for removal of pollutants, IITM said, adding that the air quality is likely to remain largely in moderate category.

Stubble burning in the neighbouring states significantly contributes to the air pollution in Delhi. Since October 6, Punjab has recorded 1,008 farm fires while Haryana had 463 fires till date.

Uttar Pradesh recorded 260 farm fires in the last eight days while Madhya Pradesh and Rajasthan accounted for 35 and 16 fires, respectively.

On October 13, paddy crop residue burning fire points were observed over Haryana (91), Punjab (132) and adjoining Pakistan.

"Winds are favourable for transport of pollutants from biomass burning. Approximately, 10 per cent contribution in PM2.5 over Delhi-NCT is likely from biomass burning on Thursday," IITM said.

The active fire events due to rice residue burning were monitored using satellite remote sensing, following the new "Standard Protocol for Estimation of Crop Residue Burning Fire Events using Satellite Data".

Between September 15 and October 10, Punjab has recorded 764 incidents of crop residue burning in 2021 compared to 2,586 in the corresponding period last year.

Punjab had recorded 1.02 lakh incidents of stubble burning in 2016. The number decreased to 67,079 in 2017; 59,684 in 2018 and 50,738 in 2019 from October 1 to November 30. The state logged 79,093 such incidents last year, according to the IARI.

Haryana saw 15,686 farm fires in 2016; 13,085 in 2017; 9,225 in 2018; 6,364 in 2019 and 5,678 in 2020.

Punjab and Haryana attract attention during the paddy harvesting season in October and November.

Farmers set their fields on fire to quickly clear off the crop residue before cultivating wheat and potato. It is one of the main reasons for the alarming spike in pollution in Delhi-NCR.