New Delhi: Delhi’s air quality was recorded in ‘very poor’ category on Tuesday as the wind continued to blow from regions where there is rampant stubble burning, authorities said, warning of a severe spike in pollution levels after Diwali even if “partial toxic crackers” are burnt compared to last year. The overall Air Quality Index (AQI) was recorded at 394, which falls in the ‘very poor’ category, according to data by the Central Pollution Control Board. On Monday, the AQI was recorded at the severe category of 434, the highest of the season, it said. On Tuesday, the PM2.5 (particles in the air with a diameter of fewer than 2.5 micrometres) level was recorded at 243 while the PM10 (particles in the air with a diameter of fewer than 10 micrometres) was recorded at 372 in Delhi.

In Delhi NCR, the PM2.5 was recorded 237 and PM10 was recorded at 366, the CPCB data said.

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’. Twenty areas in Delhi recorded ‘severe’ air quality, while 13 areas recorded ‘very poor’ air quality.

Authorities attribute the continuous pollution to the change in wind direction, which is now blowing from the direction of stubble burning areas of Punjab and Haryana. About 14 per cent of the PM2.5 pollution in Delhi was caused due to stubble burning, while 33 per cent of the PM2.5 pollution in Delhi on Monday was caused due to stubble burning, authorities said.

Winds coming from North-westerly direction is bringing the influence of biomass burning pollutants in Delhi-NCR which may continue up to Wednesday morning, the Indian Institute of Tropical Meteorology said.

Delhi’s air quality is expected to deteriorate to ‘severe plus emergency’ category after Diwali, the Centre-run System of Air Quality Forecasting and Research (SAFAR) said. “Even if 50 per cent of a total load of toxic firecrackers as compared to Diwali-2017 is added, the prevailing weather conditions will aggravate the high smoke level and make air quality to persist in severe range for at least two days on November 8 and November 9,” the SAFAR said in a report.

The PM10 is expected to reach 575 and PM2.5 is expected to reach 378 a day after Diwali, recording the worst air quality of the year, it said.