A view of the city skyline at sector-30 near Star Mall, in Gurugram.(Parveen Kumar/Hindustan Times)
A view of the city skyline at sector-30 near Star Mall, in Gurugram.(Parveen Kumar/Hindustan Times)

Gurugram breathes its cleanest air this year; rain, humidity key reasons

In July 2018, Gurugram saw 17 moderate air days. This year, there were 3 good days, 14 satisfactory days so far.
Hindustan Times, Gurugram | By HT Correspondent
UPDATED ON JUL 30, 2019 09:10 AM IST

Since Sunday, the city has been breathing its cleanest air of the year so far. Gurugram has had two consecutive days of “good” air as per the Central Pollution Control Board’s (CPCB) air quality index (AQI).

On Monday, the city’s daily AQI value stood at 39, down from 41 the previous day — Gurugram’s lowest AQI reading this year, which experts said could be attributed to meteorological conditions.

On Sunday morning, the concentration of the city’s most prominent pollutant, PM2.5, dropped to a minimum of 2ug/m3, which is well below the safety threshold of 60ug/m3.

The daily average PM2.5 concentration on Sunday, meanwhile, was 22ug/m3. The level rose slightly to 34ug/m3 on Monday but remained in the “good” category of the AQI.

According to a CPCB forecast, air quality in Gurugram will remain in the “good” category for at least three more days, with a maximum AQI reading of 43.

Experts and officials said that these numbers are typical for July, which usually sees the city’s most favourable air quality in its annual pollution cycle.

While the city was recognised as the most polluted in the world (concerning particulate matter concentrations) by a Greenpeace study last year, meteorological changes provide a much-needed respite during the rainy season, when precipitation and high relative humidity levels can significantly cut pollution levels.

In July 2018, the city did not see any “good” air days (when the AQI value dips below the 50 mark), though it saw 17 “moderate” air days, eight “satisfactory” air days, and one “poor” air day.

Data for five days in July last year was not captured due to a dysfunctional air quality monitor. The average AQI reading for the month was about 104 (moderate).

By comparison, this month so far has seen three “good” air days, 14 “satisfactory” air days, seven “moderate” air days, and two “poor” air days. Data for one day was not captured due to a dysfunctional air quality monitor. The monthly average AQI reading for July so far is around 111 (also moderate).

While the air is better this year than the same period last year, the region has seen a much drier monsoon in 2019.

“With a deficit in rainfall, pollution levels should be much higher this year, but it seems that they are only slightly higher,” a senior scientist at the CPCB’s air quality lab in Delhi said. He also pointed out that the number of “satisfactory” air days for July between 2018 and 2019 have increased, while “moderate” air days have decreased.

VK Shukla, head of the CPCB’s air quality lab, added, “The numbers are hopeful because rainfall has a large impact on air pollution levels.” Shukla said that he could not make a definitive comment about improvement in Gurugram’s air quality without analysing the data firsthand, but said, “We have been noticing gradual improvement year after year in the Delhi-NCR, so this fits the trend.”

Earlier this month, union minister of environment, forests and climate change Prakash Javadekar submitted data in the Parliament suggesting that levels of a prominent pollutant, PM10, have dipped by 20% between 2016 and 2018, dropping from an average of 278ug/m3 to 223ug/m3.

Javadekar also submitted that Delhi has had 33% fewer “poor” air quality days than two years ago.

Experts, however, said that the reduction in air pollution data should not be taken at face value.

A senior researcher with the Centre for Policy Research in Delhi, requesting anonymity, said, “There are many data constraints, such as erroneous observations, poor data collection, and abnormal deviations, which make it incredibly hard to make definite inter-year comparisons. An increase in the number and spatial coverage of air quality monitors in the NCR is also likely to skew any accurate observations.”

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