NEW DELHI: A thick blanket of haze enveloped the city on Friday, as pollution levels soared to the deep end of the ‘severe’ zone – the highest for this season and even worse than the post-Diwali spike. In a review of the worsening air quality, the Central Government’s pollution watchdog has advised people to limit outdoor exposure and reduce private vehicle usage by at least 30 per cent. The advisory has come, as there is no change likely in the current meteorological conditions at least till over the next five days. Low surface winds allowing no dispersion and an increased share of smoke from farm fires in neighbouring states has led to the spike.
The sub-committee on Graded Response Action Plan (GRAP) – an emergency action plan for winters to tackle different levels of air pollution– also said that since there was no improvement in the situation likely till November 18, states concerned and implementing agencies must be in “complete readiness” for implementation of measures under the ‘emergency’ category of GRAP, in addition to the measures under ‘severe’ category in force.
As per the Central Pollution Control Board (CPCB), Delhi’s air quality index (AQI) spiked to 471, just short of the severe plus mark of 500. Besides, the PM 2.5 (fumes, smoke) and PM 10 (coarse particles such as road dust) levels – the most prominent pollutants in Delhi’s air that can adversely impact public health – shot up by six times the permissible limit and breached the emergency threshold in the wee hours on Friday. By 8pm, it had been 19 hours that the PM levels continued to remain in the emergency zone.
When these levels remain so for 48 hours and more, ‘emergency’ measures under the GRAP such as ban on construction, entry of trucks in the city and closure of schools, among others come into force.
As per CPCB data, the PM 2.5 levels on Friday at 8pm were 376 ug/m3, breaching the emergency mark of 300ug/m3 while the PM 10 levels were 573 ug/m3, beyond the emergency mark of 500ug/m3.
In India, the 24-hour average permissible standard for PM 2.5 concentration is 60ug/m3 while for PM 10 it is 100ug/m3.The minutes of the meeting of the sub-committee that has on board NCR states, stated that the PM 2.5 and PM 10 levels crossed the emergency threshold at 1am and 3am, respectively on Friday. “It was also noted that meteorological conditions will be highly unfavourable for dispersion of pollutants till November 18 in view of low surface winds and calm wind conditions during the night,” it said.
Stagnant weather conditions
According to India Meteorological Department (IMD) scientists, while long range transport winds are coming from the northwest, which are bringing in plumes of smoke from crop stubble burning in Punjab and Haryana – where the activity is at peak – the local surface winds, which disperse the pollutants hanging in the air are too slow and further become calm towards the evening.
V K Soni, senior IMD scientist, said that, the surface winds during the day are just 4-6 kmph, which is not sufficient for dispersion of pollutants. He said that the absence of adequate sunlight and the shallow mixing height (the vertical height at which pollutants are suspended in the air) further allow pollutants to settle close to the earth’s surface.
Impact of spike in farm fires
Adding to the already high concentration of pollutants, the increase in the share of stubble burning to Delhi’s PM 2.5 levels spiked to 35 per cent on Friday with total fire counts being 4,056 (almost 4,000 only from Punjab), as compared to Thursday when the share was 26 per cent and the total fire count of the day was 3,331.The union ministry’s air quality forecasting wing said that the air quality is likely to be the same on Saturday.
NBCC fined R5L for flouting norms
New Delhi: The National Building Construction Corporation has been fined Rs 5 lakh for violating dust control norms at a project in Karkardooma in East Delhi, Environment Minister Gopal Rai said on Friday. Rai kicked off the second leg of the anti-dust campaign on Friday which will continue until December 12. The minister said all government departments have been asked to create anti-dust cells and work in coordination with the Delhi Pollution Control Committee. ‘In phase one, 450 of 2,500 construction sites inspected were found violating norms. Fines totalling Rs 1.3 crore was collected,’ he said.
CPCB advisory says
Particulate Matter levels
Breached the emergency threshold in the wee hours on Friday. At 8pm on Friday, the PM levels continued to be in the emergency category for 19 hours. When these levels remain so for 48 hours and more, ‘emergency’ measures under the GRAP such as ban on construction, entry of trucks in the city and closure of schools, among others come into force
PM 2.5 levels
376 ug/m3 at 8pm (emergency mark: 300ug/3; permissible standard: 60 ug/m3)
PM 10 levels
573 ug/m3 at 8pm (emergency mark: 500 ug/m3; permissible standard: 100ug/m3)
Major impact of stubble burning led to the spike
35% Share of stubble burning in Delhi’s PM 2.5 levels spiked to 35% on Friday with total fire counts at 4,056, as compared to Thursday when the share was 26% and the total fire count was at 3,331
