NEW DELHI: The city's air quality deteriorated with many areas now facing severe pollution. The winds in the Delhi region were calmer and, therefore, did not efficiently dispersed pollutants. Besides, north-westerly winds also brought pollutants created by stubble burning in neighbouring states. There was an increase in local pollution sources too.

Delhi's Air Quality Index (AQI) on a scale of 0-500 was 367 at noon, which improved marginally to 364 by 4pm and to 361 by 8pm.While this indicated the air quality was in the 'very poor' category, the air readings in Anand Vihar, Jahangir Puri, Dwarka and Vivek Vihar fell to the 'severe' category in the early afternoon, with Anand Vihar being the worst polluted, logging an AQI of 406 at noon and a fall to 433 by 8 pm.
The city's average AQI on Tuesday was 327. An AQI of 301 to 400 is considered 'very poor' and between 401 and 500, 'severe.
According to the forecast made by the Indian Institute of Tropical Meteorology, Pune, Delhi air quality is not expected to improve over the next six days. "The air quality is likely to be in the 'very poor" category from Oct 24 to 26. The outlook for the subsequent six days: The air quality is likely to be in the 'very poor' to 'severe' categories. Meteorological conditions are unfavourable for effective dispersion of pollutants as calm winds prevail during the night," according to the air quality early warning system.
Meanwhile, the proportion of pollutants from stubble burning in Delhi foul air increased from 3.2% on Monday to 8% on Tuesday. The estimated share for Wednesday was not shared by IITM's Decision Support System, which also withdrew the information on the estimated forecast or projections of the possible share of stubble burning for the next few days. DSS had earlier estimated the share of stubble burning in the city's net PM2.5 levels at 11.1% for Wednesday and 15.1% for Thursday.
According to a report by ICAR, on Wednesday, there were 57 rice harvest remnant fires reported in Punjab, 15 in Haryana, 68 in Uttar Pradesh and none in Delhi on Wednesday. So far, since Sept 15, there have been 1,638 counts of stubble burning in Punjab, 680 in Haryana, 808 in UP and 11 in Delhi.
On Wednesday, transport remained the major source of local pollution in the city, contributing to 13.5% of all pollution, followed by 4.8% from Sonipat, 4.1% from Panipat, 3.4% from Delhi's residential emissions, 3.2% from Ghaziabad and 3% from industries. According to the Central Pollution Control Board, the PM2.5 levels oscillated between 133.7 to 160.8 micrograms per cubic metre on Wednesday, rising as the day proceeded. While the national standard for PM2.5 is 60 units, WHO's safe limit is 15 micrograms per cubic metre.
The weather analysts expected no major change in the meteorological conditions and the north-westerly winds are likely to continue over the next few days, bringing additional smoke from the states where harvest stubble is being burnt in the fields.