Delhi's Air Quality Index (AQI) improved on Tuesday after levels of Particulate Matter (PM), the solid and liquid particles suspended in air, many of which are hazardous, reduced to some extent, but it still figured in "very poor" category, according to Central Pollution Control Board (CPCB) data.
On Monday, the AQI in Delhi had reached 445 due to a large number of firecrackers being burst on Diwali on Sunday night, which took pollution to "severe" category. Despite fewer firecrackers being burst on Monday night, the AQI came down to just 389 on Tuesday owing to adverse climatic conditions, the data said.
High humidity, low wind speed and low temperatures meant the pollutants hovered very close to the surface and could not be dispersed.
"Today (Tuesday), speed of wind is too low. In the afternoon, it is about 0.3kmph horizontally, while it is zero vertically. It means pollutants remained in the air. We will have to study metereological conditions for next few days to find the pollution levels in Delhi," said Vivek Chatopadhyay, senior researcher with NGO - Centre for Science and Environment (CSE).
The PM 2.5 and PM 10 levels were found to be the prominent pollutant on both consecutive days.
According to CPCB, the PM 2.5 level, or particulate matter with size of less than 2.5 microns that can reach the thinnest arteries of lungs in our body, had reached 430 microns per cubic meter on Diwali night.
The PM 10 level, which is slightly bigger than PM 2.5 and very harmful for the respiratory system, had touched very high levels too on the same day.
CPCB said there was not any increase in noise pollution this Diwali as compared with the last Diwali. However, concentration of Nitrogen dioxide (NO2), sulfur dioxide (SO2) gases was found higher this year.
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