The north to northwesterly winds blew the clouds of dust that formed owing to the implosion towards greater Noida and further towards Uttar Pradesh, Hindustan Times quoted experts.
Reportedly, just an hour before the demolition was to be conducted, the wind direction around the Supertech twin towers changed towards east, which made dust particles drift towards Greater Noida and Bulandshahr instead of Delhi.
For the last one week, the direction of wind was towards the west but the change was sudden, Regional Officer, Uttar Pradesh Pollution Control Board, Praveen Kumar said.
The wind direction therefore helped Delhi to maintain a stable Air Quality, as was evident from the Air Quality Index (AQI). The nearest Delhi Pollution Control Committee (DPCC) air quality monitoring stations at Okhla Phase-2, Dr Karni Singh Shooting Range and Patparganj did not show any spike in the PM 10 concentration from 3pm onwards.
The Indian Metrological Department (IMD) forecast also shows that the wind direction is likely to remain northwesterly in the next 24 hours. A“Wind speed on Sunday was strong, but it was northwesterly and therefore, will not impact Delhi much. Rain is also expected in Delhi on Monday, so any dust in the air even towards Delhi is likely to settle and there will not be any impact of this event," said a met official.
National capital Delhi is no stranger to dust storm, ‘poor air quality’ or ‘severe air quality’. Dust, which comprises of coarser particles, is generally known to increase the local PM 10 concentration as opposed to PM 2.5.
The DPCC reading registered a small spike in the PM 10 concentration levels following the demolition and that remained the only change. According to the Hindustan Times report, the hourly PM 10 concentration at the station increased from 130 micrograms per cubic metre at 2pm to a reading of 149 micrograms per cubic metre at 3pm, before dropping back down to 132 micrograms per cubic metre at 4pm.
“Wind direction is north to northwesterly and following the explosion, the dust began to gradually blow towards Greater Noida. Wind direction is likely to stay northwesterly till at least Monday afternoon and after that, it may switch to easterly, however, even then, Delhi is unlikely to be impacted by this dust as a change in wind direction generally leads to calm winds," said Mahesh Palawat, vice president at Skymet meteorology.
Delhi’s air quality index (AQI) was, meanwhile, recorded in the ‘moderate’ category on Sunday, with an AQI reading over a 24-hour period recorded at 119 as per Central Pollution Control Board’s daily national bulletin, which is released at 4pm. This was slightly higher than the average 24-hour reading of 105 (moderate) on Saturday.
According to the ‘Early Warning System For Delhi’ developed by the Ministry of Earth Sciences (MoES), air quality is unlikely to deteriorate over the next few days.
“The air quality over Delhi is likely to remain in the ‘moderate category’ on Sunday and Monday. The air quality is then likely to improve but remain in the ‘moderate’ to ‘satisfactory’ category on Tuesday and will improve to the ‘satisfactory’ category on Wednesday," the forecast issued by the MoES-developed system states.
