Delhi's air quality was recorded in the "poor" category for the sixth consecutive day on Monday. The national capital recorded a 24-hour average air quality index (AQI) of 278, according to Delhi Pollution Control Committee (DPCC) data.
Delhi's air quality had turned poor on Wednesday, the first time in since June 29, with the Central Pollution Control Board recording a 24-hour average AQI of 215.
In Anand Vihar, the AQI stood at 275, in Rohini at 263, in ITO at 275, and in Nehru Nagar 229, according to DPCC data at 8 am on Monday.
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 Ministry of Earth Sciences' air quality monitor, SAFAR noted that a total of 448 farm fires were observed in Punjab, adjoining Pakistan, Haryana and Uttar Pradesh which impacted Delhi's air quality in the last six days.
However, the wind direction will change from northwesterly to southeasterly and the impact of farm fires will reduce, it said.
On Monday morning, Delhi's minimum temperature settled at 22 degrees Celsius. The maximum wind speed was 8 kilometers per hour. Low temperatures and stagnant winds helped in the accumulation of pollutants near the ground, affecting air quality.
High levels of air pollution in Delhi is a year-round problem, which can be attributed to unfavourable meteorological conditions, farm fires in neighbouring regions and local sources of pollution.
According to an analysis by the Council on Energy, Environment and Water, a Delhi-based think tank, transportation contribute the most -- 18 to 39 per cent -- to Delhi's air pollution.
Road dust is the second-largest source of air pollution in the city (18 to 38 percent), followed by industries (2 to 29 per cent), thermal power plants (3 to 11 per cent) and construction (8 per cent).