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Even as an "emergency" under the Graded Response Action Plan (GRAP) was officially imposed in Delhi-NCR on Thursday and the Delhi government announced the third phase of the odd-even traffic rule from November 13, a change in the wind direction is set to add further 'poison' to the national capital's air on Friday, officials said.
Delhi Transport Minister Kailash Gehlot announced the third phase of the odd-even scheme from November 13 to 17.
However, according to the members of the Supreme Court-appointed Environment Pollution Prevention and Control Authority (EPCA), November 13 is too late as the "emergency or severe-plus" category under GRAP calls for immediate implementation of the odd-even car rationing scheme.
"We had been telling them (Delhi government) to stay ready since last week and even during Tuesday's EPCA meeting... The Delhi government said it was prepared to roll out the odd-even right away... Now they are saying they can roll it out only on Monday (November 13). This won't help much," CPCB Member Secretary and EPCA Member A. Sudhakar told IANS.
The "emergency" or "severe-plus" situation arises after the major pollutants -- PM2.5 and PM10, or particles in air with diameter less than 2.5 and 10mm, remain above 300 and 500 units, respectively, for at least 48 hours.
The Central Pollution Control Board (CPCB) on Thursday informed that both PM2.5 and PM10 had been beyond the "safe limits" for the past 52 hours or since 7 a.m on Tuesday, November 7.
On Thursday (since Wednesday evening), all the 10 monitoring stations of the System of Air Quality and Weather Forecasting and Research (Safar) recorded "beyond severe" or 500-plus units of PM10 and PM2.5. As per SAFAR, the average PM2.5 was 546 units and PM10 was 895.
According to the CPCB, at 5 p.m, the average PM2.5 reading on the Air Quality Index (AQI) in Delhi-NCR across 20 active stations (including Alwar in Rajasthan) was 478 units (on a scale of 0 to 500).
The safe limit for PM2.5 and PM10 as per international standards is 25 and 60 microgrammes per cubic meters, while as per national standards it is 40 and 100 units, respectively.
Meanwhile, forecasting some relief for Delhi-NCR from November 14 onwards, the India Meteorological Department (IMD) said rain in parts of Haryana, western Rajasthan, Uttar Pradesh and Punjab would help disperse the effluents, thereby normalising the air quality in Delhi.
"Relief is likely from Sunday, when the wind speed would increase. However, the western disturbance, which is expected to arrive in this region from November 14, would bring major relief as it could rain. This is so far the best hope under the present conditions," Charan Singh, weather forecast chief at IMD, told IANS.
However, the relief would come only after Delhi has seen its worse, as air quality in the capital, which is already "beyond severe", is set to deteriorate further since the light winds from Punjab and Haryana started entering Delhi on Thursday.
As the stubble burning continues unabated in Punjab and Haryana, which is also a major cause of the present air quality situation in Delhi, the winds coming from there would further affect the air in Delhi-NCR.
According to the IMD and private weather forecasting agency Skymet, the wind speed is less -- five to 10 kmph, but this is enough to bring effluents and not disperse them due to its low speed.
"There would be a slight variation in the air quality tomorrow (Friday). The winds which were for now only westerly have changed into north-westerly coming from Punjab," Singh added.