Analysis: 'Severe' Air Quality In Delhi; How Bad Is It In Other Cities?

A thick blanket of toxic haze enveloped Delhi for the second consecutive day as the air quality deteriorated to the "severe plus" category today, prompting the AAP-led Delhi government to shut primary schools for two days. 

Delhi's 24-hour average air quality index stood at 468 on Friday which falls in the "severe plus" category, a stage at which all emergency measures, including a ban on polluting trucks, commercial four-wheelers, and all types of construction, are mandated to be initiated and enforced in the National Capital Region.

How bad the air pollution was in the past 24 hours?

According to an analysis by Respirer Reports, a part of Respirer Living Sciences, the level of PM 2.5, Particulate Matter (PM) with less than 2.5 micrometres in diameter, crossed the 600 micrograms/cubic metre mark in at least six places while the average PM 2.5 level was lower. 

In Noida's sector 62, the PM 2.5 level was at 676.2 while the average was 445.8. At least two places were in the heart of the capital - RK Puram and Punjabi Bagh, where the levels were 652.5 and 610, respectively.

In all, 'severe' air quality i.e. PM 2.5 levels above 250 micrograms/cubic metre were reported at 51 monitoring stations, almost all of them in the Delhi-NCR region. 

Today's Analysis

The PM 2.5 pollution rose above the 500 micrograms/cubic metre mark in Delhi. One location in the capital saw PM 2.5 rise above 500, while two areas were only slightly below 500. 

In West Delhi's Mundka, the PM 2.5 at 10 am was reported at 516.2. Punjabi Bagh in west Delhi was at the second spot with a PM 2.5 level of 496.9. 

Out of the 10 most polluted spots in the Delhi-NCR region, eight were in Delhi. 

In third place was RK. Puram in southwest Delhi, with PM 2.5 at 489.5. At fourth and fifth places were Wazirpur and Bawana in North West Delhi, with PM 2.5 at 483.2 and 486, respectively. 

Despite the 'severe' PM 2.5 levels in the national capital, Greater Noida in Uttar Pradesh was the most polluted city in the country, with an average PM 2.5 concentration of 401.5 micrograms/cubic metre. 

Delhi was a close second with the average daily PM 2.5 at 379.2 and Sonipat in Haryana was third with PM 2.5 at 358. 

Air Quality In Other Cities

The number of cities with 'severe' air quality shot up to 12 from one in just two days. Uttar Pradesh's Greater Noida replaced Rajasthan's Hanumangarh as the most polluted city in India in the last 24 hours, while Mizoram's Aizwal was once again the least polluted city.

In the last 24 hours, Delhi was still the most polluted capital in India but Bhopal, which was at the third spot yesterday, is now the second most polluted capital in India with a PM 2.5 level of 102.1, followed by Agartala at 94.3, Jaipur at 82.5. Chandigarh is at the fourth spot with PM 2.5 level at 80.9, followed by Kolkata at 77.9 and Lucknow at 76.2, Patna at 75.3.  

In Mumbai, the number of locations with PM 2.5 levels in the 'poor' category in the last 24 hours went up from four on November 2 to five today. 

The concentration values also went up - the most polluted place today was Navy Nagar-Colaba, with a PM 2.5 level of 107.2, while yesterday, it was Mulund West, with a PM 2.5 at 102.3. 

A seven-day average for these locations showed that Sion was the most polluted place in Mumbai. 

Least Polluted Cities

In the last 24 hours, Mizoram's Aizwal was the least polluted city in India with a PM 2.5 level of 4.4, followed by Puducherry at 6.1. 

The seven-day average of the least polluted cities shows Aizawl as the least polluted city, followed by Silchar in Assam and Sivasagar. Karnataka's Hubballi and Vijayapura were third and spot respectively in the seven-day average data.