Delhi's 24-hour average Air Quality Index (AQI) was recorded at 359, the highest so far this season.
Haze enveloped Delhi and its suburbs on Tuesday, with the capital recording 'very poor' air quality for the fourth day on the trot.
According to a numerical model-based system developed by the Indian Institute of Tropical Meteorology in Pune, vehicular emissions (11 per cent to 16 per cent) and stubble burning (7 per cent to 16 per cent) currently stand as the two major contributors to the city's air quality.
It also showed that pollution sources in Gautam Budh Nagar, Uttar Pradesh, are responsible for up to 14 per cent of the air pollution in the capital.
The city's 24-hour average Air Quality Index (AQI) was recorded at 359, the highest so far this season. It was 347 on Monday, 325 on Sunday, 304 on Saturday and 261 on Friday, 256 on Thursday, 243 on Wednesday and 220 on Tuesday.
The AQI was 232 in neighbouring Ghaziabad, 313 in Faridabad, 233 in Gurugram, 313 in Noida and 356 in Greater Noida.
An AQI between zero and 50 is considered 'good', 51 and 100 'satisfactory', 101 and 200 'moderate', 201 and 300 'poor', 301 and 400 'very poor', and 401 and 500 'severe'.
The city's air quality deteriorated to the 'very poor' category on Saturday due to slow wind speed at night and a dip in temperature.
The air quality is expected to remain 'very poor' for a few more days, according to the Centre's Air Quality Early Warning System for Delhi.
Delhi's air quality in October 2023 was the worst since 2020 with meteorologists attributing it to the lack of rainfall.
The capital recorded an AQI of 210 this October, compared to 210 in October last year and 173 in October 2021, according to Central Pollution Control Board (CPCB) data.
Delhi saw just one rainy day (5.4 mm of precipitation) in October 2023, in contrast to six in October 2022 (129 mm) and seven in October 2021 (123 mm).
The Centre's Commission for Air Quality Management (CAQM) said the average wind speed during October 2023 was relatively low and spells of absolutely "still" conditions were also observed during the month.
Starting Wednesday (November 1), only electric, CNG and BS VI-compliant diesel buses will be allowed to operate between Delhi and the cities and towns of Haryana, Uttar Pradesh and Rajasthan falling within the NCR, according to directions issued by the CAQM.
In an effort to reduce pollution levels, the Centre announced in April 2020 that all vehicles sold in India must comply with the Bharat Stage VI (BS-VI) emission standards.
The Bharat Stage emission standards set legal limits on the amount of air pollutants such as carbon monoxide and particulate matter that vehicles in India can emit. These standards focus on improving emission control, fuel efficiency and engine design.
As vehicle manufacturers provide vehicles that meet these new norms, oil companies supply fuel that adheres to the BS-VI standards, known as the world's cleanest fuel.
Unfavourable meteorological conditions and a cocktail of emissions from firecrackers and paddy straw burning, in addition to local sources of pollution, push the Delhi-NCR's air quality to hazardous levels during winter.
According to an analysis conducted by the Delhi Pollution Control Committee (DPCC), the capital experiences peak pollution from November 1 to November 15, when the number of stubble burning incidents in Punjab and Haryana goes up.
The CAQM, a statutory body responsible for formulation of strategies to reduce pollution in Delhi-NCR, said on Monday that the number of stubble burning incidents in Punjab and Haryana since September 15 has reduced by around 56 per cent and 40 per cent, respectively, compared to the corresponding period last year.
In the period between September 15 and October 29, the cumulative number of farm fires in Delhi, Punjab, Haryana and NCR areas of Rajasthan and Uttar Pradesh reduced from 13,964 in 2022 to 6,391 in 2023, it said.
In Punjab, there were 5,254 stubble burning incidents during this 45-day period this year, compared to 12,112 in 2022 and 9,001 in 2021. This represents a reduction of 56.6 per cent and 41.6 per cent, respectively.
Haryana reported 1,094 stubble burning cases during this 45-day period this year, significantly lower than 1,813 in 2022 and 2,413 in 2021. This reflects a reduction of 39.7 per cent and 54.7 per cent, respectively.
The Punjab government is aiming to reduce farm fires by 50 per cent this winter season and eliminate stubble burning in six districts -- Hoshiarpur, Malerkotla, Pathankot, Rupnagar, SAS Nagar (Mohali) and SBS Nagar.
According to the state's action plan to curb paddy straw burning, about 31 lakh hectares of land in the state is under paddy cultivation. This is expected to generate around 16 million tonnes of paddy straw (non-basmati), which will be managed through in-situ and ex-situ methods.
Haryana estimates that about 14.82 lakh hectares of land in the state is under paddy cultivation. This is expected to generate over 7.3 million tonnes of paddy straw (non-basmati). The state will attempt near elimination of farm fires this year.
The Delhi government launched a 15-point action plan last month to mitigate air pollution during the winter season, with a strong emphasis on addressing dust pollution, vehicular emissions and open burning of garbage.
In keeping with the practice of the last three years, the Delhi government last month announced a comprehensive ban on the manufacture, storage, sale and use of firecrackers within the city.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)