Rain, cyclonic disturbances led to cleaner March: Experts

Experts attributed this to the irregular weather phenomena such as rain and cyclonic disturbances, which have prevailed this past pollution cycle.

This month, air quality in the city has shown significant improvement as compared to the same period last year, Central Pollution Control Board (CPCB) data shows.

Rain, cyclonic disturbances led to(Sanjeev Verma/HT Photo)

Experts attributed this to the irregular weather phenomena such as rain and cyclonic disturbances, which have prevailed this past pollution cycle.

The phenomena led to a ‘wetter’ winter and spring, experts maintained.

This March, Gurugram did not have a single day of ‘very poor’ air as compared to six days in March, 2018.

Moreover, the city had six days of ‘satisfactory’ air as opposed to no such days in March, 2018.

According to the CPCB’s daily air quality index (AQI) bulletin, the city witnessed six days of ‘satisfactory’ air quality, 19 days of ‘moderate’ air quality and four days of ‘poor’ air quality this month.

In March 2018, however, the city had zero days of ‘satisfactory’ air, 12 days of ‘moderate’ air, eight days of ‘poor’ air and six days of ‘very poor’ air.

Gurugram was missing from the AQI bulletin for one day, on March 9. Last year, it was missing from the AQI bulletin for five days.

“Air quality usually begins improving in the month of March. This year, in particular, we have observed higher relative humidity than last year, which makes particulate matter heavier and causes it to settle down. There have also been frequent western disturbances blowing from the middle-east at high speed, causing long-range transportation of dust and dispersal of particulate matter, which is the primary pollutant in Gurugram,” said Guneet Singh, founder of a city-based non-profit which tracks air quality.

March is a transition period between the winter and summer, and atmospheric factors which influence air quality, such as wind speeds, temperature and humidity, are in a state of flux. As a result, one usually sees a range of ‘very poor’ to ‘satisfactory’ air days around this time.

This March, however, Gurugram’s highest AQI score was 271 (‘poor’) as opposed to 366 (‘very poor’) in March 2018 due to favourable meteorological conditions. “On the whole, we should be really thankful to the weather gods for giving us a better winter and spring this year,” Singh maintained.

Air quality is expected to stabilise in the coming weeks. “Around April, you will find pollution levels settling down in the lower or middle region of the air quality index’s ‘poor’ category,” said Dipankar Saha, former head of the CPCB’s air quality lab.

He also said that this would be the case throughout May and June as well.

However, during the summer months in 2018, AQI levels touched ‘severe’ and ‘severe plus’ levels due to incoming dust storms from Afghanistan. It is likely that we will see the same phenomenon this year toward the end of the summer, experts warned.

“Then, once monsoon arrives, we will have a couple of months of favourable air quality in the NCR. It is usually the only time of the year when we have ‘good’ air days in the region,” Saha explained