NEW DELHI, Oct. 30 (Xinhua) -- Air over the Indian capital continued to be severely polluted as smog coupled with calm winds have left a layer of haze, choking the environment and turning the air toxic.
The burning of farm residues, or stubble, by farmers in nearby states of Haryana and Punjab continues to be the biggest threat to air quality in Delhi and nearby areas.
The situation is likely to remain unchanged for the next couple of days, said a weather forecast.
The pollution caused by bursting firecrackers on the "Deepawali" festival on Sunday has further aggravated the situation.
On Wednesday morning the skies over Delhi continued to be smoky grey with the air quality hovering between the "very poor" and "severe" category and the overall air quality index (AQI) being over 400, which is considered "severe."
According to the air quality monitor System of Air Quality and Weather Forecasting and Research (SAFAR) from Ministry of Earth Sciences, the levels of PM2.5, tiny particulate matter less than 2.5 microns that can enter deep into the lungs, reached 740 in Delhi University in north Delhi area, 12 times higher than the 0-60 category of "good."
At 8:00 a.m. local time, Delhi's overall AQI was 422, which was worse than Tuesday's 414. The air quality in nearby city of Noida in northern state of Uttar Pradesh was no better with the AQI settling at 270 on Wednesday morning.
An AQI between 0-50 is considered "good", 51-100 "satisfactory", 101-200 "moderate", 201-300 "poor", 301-400 "very poor", and 401-500 "severe". Above 500 is "severe-plus emergency" category. The higher the AQI value, the greater the level of air pollution and the greater the health concern.
Throughout Tuesday the sunlight remained dim as the haze enveloped the air over Delhi and nearby areas, with the air quality slipping into the "severe" category.
Among the capital city's 37 air quality monitoring stations, 26 recorded AQI in the "severe" category on Tuesday, said media reports.
