At time when pollutant levels recorded three fold higher than prescribed standards, Delhi Environment Minister Imran Hussian issued challan of Rs 50,000 each to two under constructions sites at Deen Dayal Upadhyay (DDU) Marg for the gross violation of environmental rules.

On Saturday, air quality recorded under very poor category for the sixth with the meteorological conditions remaining unfavourable for dispersion of pollutants, authorities said.

According to Central Pollution Control Board (CPCB) data, the overall air quality index (AQI) of Delhi was 322, which fell in the "very poor" category.

The CPCB said in 27 areas of the national Capital, the air quality was in the "very poor" category, while in five areas, it was recorded in the "poor" category.The PM2.5 (fine particulate matter in the air with a diameter of less than 2.5 micrometre) level was recorded at 155 and the PM10 level at 310, it added.

Ghaziabad, Faridabad and Noida in the national Capital Region (NCR) recorded a "very poor" air quality while Gurgaon recorded a "poor" air quality, the CPCB data showed.

Delhi's air quality has been in the "very poor" category for the past one week with several areas recording a "severe" air quality, the authorities said.

According to the Centre-run System of Air Quality and Weather Forecasting (SAFAR), the air quality is likely to remain in the same category with a slight decline in the pollution levels by Sunday due to an enhanced wind speed.

"However, it (AQI)) is likely to increase thereafter for the next two days to register in the upper range of the 'very poor' level. This deteriorating AQI on December 2-3 would mainly be due to expected adverse meteorological conditions and a decline in the wind speed. The contribution of long-range dust or stubble biomass is negligible," it said.