Delhi's air quality very poor, vehicular emissions largest contributor

Delhi's air quality fluctuated b/w very poor & severe due to unfavourable meteorological conditions. Vehicular emissions accounted for 38-40%, secondary inorganic aerosols 30-35%.

Delhi's air quality fluctuated between the very poor and severe categories on Thursday as unfavourable meteorological conditions hindered the dispersion of pollutants.

Recent findings from a joint project by the Delhi government and IIT-Kanpur found that vehicular emissions accounted for about 38 percent of the capital's air pollution on Wednesday. This is projected to rise to 40 percent on Thursday.

Secondary inorganic aerosols -- particles such as sulfate and nitrate that are formed in the atmosphere due to the interaction of gases and particulate pollutants from sources like power plants, refineries, and vehicles -- is the second major contributor to Delhi's foul air, accounting for 30 to 35 percent of the air pollution in the city over the last few days.

Calm winds and low temperatures are allowing accumulation of pollutants and relief is unlikely over the next few days, an official at the India Meteorological Department (IMD) said.

Delhi's Air Quality Index stood at 393 at 9 am on Thursday. Its 24-hour average AQI, recorded at 4 p.m. every day, stood at 401 on Wednesday. It was 397 on Tuesday. It was 358 on Monday and 218 on Sunday, 220 on Saturday, 279 on Friday and 437 on Thursday.

Neighbouring Ghaziabad (358), Gurugram (325), Greater Noida (343), Noida (337) and Faridabad (409) also recorded very poor to severe air quality.

An AQI between zero and 50 is considered good, 51 and 100 satisfactory, 101 and 200 moderate, 201 and 300 poor, 301 and 400 very poor, 401 and 450 severe and above 450 severe plus.