New Delhi, Nov 3 (IANS): With stubble burning share in Delhi's air pollution set to increase over the next three days, SAFAR has projected an AQI of 500 plus on November 5 even if Delhiites burst 50 per cent less crackers compared to last year.

The overall air quality of Delhi is at the lower end of "very poor" category and predicted to start deteriorating from Thursday onwards to touch the upper end of the "very poor" range on November 4, the SAFAR advisory said.

SAFAR, or the System of Air Quality and Weather Forecasting And Research under the Indian Institute of Tropical Meteorology (IITM) - an agency under the Ministry of Earth Sciences - said as per sensitivity simulation, stubble share on November 4 is predicted to increase to 20 per cent and will touch a peak of 35-40 per cent on November 5 and 6, if fire counts are considered same as on Wednesday (3,500-4,000).

This is largely due to transport level winds reaching Delhi from the northwest, where stubble burning large hot spots are expected, SAFAR said.

In addition, very calm local Delhi wind conditions with little ventilation is expected for the next three days.

Under zero firecracker emission scenarios, the level of PM 2.5 is predicted to be at the upper end of "very poor" during November 4 to 6.

"However, if we consider 50 per cent of additional fire cracker load of 2019, then AQI is predicted to enter the 'severe' category during November 4 to 6. It is predicted to improve slightly on November 6 evening onwards but will fluctuate between high-end of 'very poor' to the 'severe' range. This is mainly due to coinciding of all three critical factors with a peak PM2.5 surpassing AQI value of 500+ on November 5," the advisory said.