Delhi’s air quality in January saw no improvement as compared to the same period last year, despite stronger windspeed and heavy rain. Air quality index data from the Central Pollution Control Board (CPCB) shows that the average air quality index value this year was 328 — the same as January 2018. The average in 2017 was much better at 304.
The number of ‘severe’ air quality days (days when the air quality index value is above 400 on a scale of 0 to 500) in January 2019 was seven, as compared to four in 2018.
An improvement in air quality was expected as lesser fog and higher average wind speed were observed during the month.
Officials at the Delhi Pollution Control Committee (DPCC), however, said a long, cold spell was partly responsible for the poorer air quality.
While higher windspeed helps disperse pollutants and improve air quality, low temperature and high humidity aids the accumulation of pollutants. “Both these factors have played a bigger part this year. The Delhi government has also commissioned a study to understand sources of pollution in the city,” said a senior government official.
The last such study was submitted to the government in 2015 and was conducted by IIT-Kanpur. It found that dust and vehicular pollution are among the biggest causes of pollution in winter months.
The air quality index value on Thursday was 359, putting it in the ‘very poor’ category.