Delhi's air pollution level dipped slightly Saturday but remained in the "very poor" category due to control measures by authorities and stagnant meteorological conditions but officials warned of deterioration in air quality to "severe" levels from Monday.
Wazirpur recorded "severe" quality air, while air quality in 34 other areas was "very poor", according to the CPCB data.
The PM2.5 level was recorded at 175. Fine particulates can be a matter of serious health concern than PM10 (particles in the air with a diameter of fewer than 10 micrometres).
Ghaziabad, Faridabad, Gurgaon, Noida and Greater Noida all recorded "very poor" air quality, according to the data.
As per data by the Centre-run System of Air Quality Forecasting And Research (SAFAR), the PM10 level in Delhi stood at 302.
An AQI between 0 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 Indian Institute of Tropical Meteorology (IITM) said the contribution from biomass fire is likely to increase in the coming days.
"The PM2.5 concentration is likely to increase sharply on Monday owing to change in wind direction and contribution from biomass burning. If significant stubble burning continues today and tomorrow in the NW region of India then its impact is very likely over Delhi and AQ may reach severe category," the IITM said.
"The air quality is likely to be in a very poor category on 03.11.2018 and 04.11.2018 and may become severe on 05.11.2018. The north-west wind direction may continue to bring the influence of biomass fire on 06.11.2018 and 07.11.2018 (Diwali days)," it said.
The SAFAR also said there could be "severe" deterioration from November 5 due to unfavourable meteorological conditions.
According to the SAFAR, 10 per cent of PM2.5 pollution in Delhi on Saturday was caused due to stubble burning.
Delhi authorities have stepped up efforts to combat pollution which includes measures like halting construction activities and regulating traffic.
There is a halt on all construction activities involving excavation. Civil construction has also been suspended in Delhi and other NCR districts, besides closure of all stone crushers and hot mix plants generating dust pollution.
The Delhi Pollution Control Committee (DPCC) has also directed the Transport Department and the Traffic Police to intensify checking of polluting vehicles and control travel congestion in the region during November 1-10.
Around 43 teams have been formed by the North Delhi Municipal Corporation for night patrolling to check incidents of burning of garbage.
Around 110 vehicles have been deployed to sprinkle water on the roads and 12 mechanical dust sweeping machines have been pressed into action.
(With inputs from agencies.)