Delhi was engulfed in a layer of dust on May 15 after undergoing overnight dust storms, reducing visibility and leading to a dip in the air quality.
The dust storms were triggered by gusty winds going at speeds of 30 to 40 kmph, according to the India Meteorological Department (IMD).
Impact on Visibility, AQI
The visibility had fallen from 4,500 metre to 1,200 metre at IGI airport from 10 pm to 11.30 pm on the night of May 14 after the dust storm, reported ANI.
The IMD said that dust advected from North Pakistan is moving towards Delhi-NCR via Punjab and Haryana. The movement occurs under strong lower-level westerly winds prevailing over Punjab and Haryana.
The IMD also stated that dust has been gradually shifting eastward, improving visibility over the Palam area of Delhi, which is currently reporting visibility at 4000 meters.
Visibility conditions above 1000 meters are not considered a significant dust storm or dust event, as per IMD.
This dusty weather comes a day after the people in the national capital experienced heat, with average temperatures soaring as high as 40.2 degrees Celsius, 0.7 notch above the season's average, reported Mint.
Fluctuating Air Quality Levels
According to the Central Pollution Control Board, the air quality in Delhi on May 15 was recorded in the “poor” category, with a reading of 289 at 11.30 am on May 15. CPCB in Anand Vihar recorded an AQI of 285, Ashok Vihar reached 292, RK Puram 310 and Bawana recorded an AQI of 303 in the evening at 4 pm on May 15.
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” and 401 and 500 “severe”.
Earlier on May 1, the Commission for Air Quality Management (CAQM) revoked the Graded Response Action Plan (GRAP) Stage – 1 in Delhi-NCR with immediate effect after the national capital’s Air Quality Index (AQI) improved to the ‘Moderate’ category.
The CAQM said in a statement that the decision was taken based on the daily average AQI provided by the Central Pollution Control Board.
“Owing to strong winds and favourable meteorological conditions, the AQI of Delhi has shown improvement and has been recorded as 184 for May 1 (Moderate category). Further, the forecast by IMD/ IITM also predicts AQI to remain ‘Moderate’ category in coming days,” the order stated.
"All the agencies of the concerned State Governments/GNCTD in the NCR, to sustain the better AQI levels as being experienced currently and not to let the air quality slip to the directions, advisories, orders, etc., issued by the Commission are followed and implemented in right earnest, including the rules/ regulations/ guidelines issued by MoEFCC and the Central Pollution Control Board and related guidelines issued by the respective State Governments/GNCTD and Pollution Control Boards/DPCC, across all contributing sectors,” it added.
