New analysis of winter air pollution (till January 11, 2021) in the cities of Indo-Gangetic Plains(IGP), carried out by Centre for Science and Environment (CSE), shows how clean air gains of the lockdown and monsoon periods have been lost with the reopening of the economy and the hostile winter weather.
Interestingly, says the analysis, the rise in pollution levels has also been synchronised across the region with varying patterns.
While this was expected, the analysis of real-time data from monitoring stations outside the National Capital Region (NCR) in the larger Indo-Gangetic Plains shows newer patterns in winter pollution this year. Even though trapping of winter pollution in the IGP is high compared to other regions, it was not as high as that in the NCR – at the same time, it was alarmingly high and synchronised despite the large distances involved. This is the challenge of this landlocked region.
This analysis is part of CSE’s air quality tracker initiative to get a deeper view of the changing patterns of air quality trends in the country. Says AnumitaRoychowdhury, CSE’s executive director in charge of research and advocacy: “This brings out the impact of the extraordinary disruption that 2020has caused. Despite the dramatic reduction in air pollution during the lockdown, pollution has bounced back across the region post-lockdown unmaskingthe high impacts of local and regional pollution with some variation in the pattern. This demands quicker regional reforms and action to curb pollution from vehicles, industry, power plants and waste burning to further bend the air pollution curve on a regional scale.”
Higher PM2.5 levels is a typical and predictable winter trend when continuous emissions from local sources including vehicles, industry, construction, and episodic pollution from biomass burning get trapped due to meteorological changes. AvikalSomvanshi, programme manager in CSE’s Urban Lab team of the Sustainable Cities programme, says: “This year, this trend has set in almost two weeks earlier in the season. There is a clear difference in the winter pollution pattern between IGP regions north and south of the NCR. Even though the average level of PM2.5 for the summer and monsoon months in 2020 is considerably lower than the previous year’s due to the summer lockdown, the PM2.5 levels thiswinter have risen beyond the 2019 levels in almost all monitored cities in Punjab and Haryana (regions north of the NCR).”
Somvanshi adds: “Cities in central and eastern UP and Bihar (regions south of the NCR) also show high winter pollution, but the levels are similar or lower compared to 2019.Combination of the reopening of the economy and changing meteorology is responsible for high winter pollution, but this regional variation calls for a more nuanced and robust pollution control strategy. The region cannot rely only on action being taken in Delhi-NCR. This demands speed and scale of action.
Data used in the analysis
The analysis is based on publicly available granular real-time data (15-minute averages) from the Central Pollution Control Board’s (CPCB) official online portal,the Central Control Roomfor Air Quality Management.
Twenty-six cities –Amritsar, Bhatinda, Jalandhar, Khanna, Ludhiana, MandiGobindgarh, Patiala, Rupnagar, Chandigarh, Ambala, Fatehabad, Hisar, Kaithal, Kurukshetra, Panchkula, Sirsa, Yamuna Nagar, Agra, Kanpur, Moradabad, Varanasi, Lucknow, Patna, Gaya, Muzaffarpur and Hajipurhave been selected for this analysis because real-time data is available for these cities.
Analysis has been done of the data recorded by six air quality monitoring stations in Patna, five in Lucknow,two in Gaya and Muzaffarpur each,and one station each in the rest of the cities under the Continuous Ambient Air Quality Monitoring System (CAAQMS) of the CPCB. Weather data for Amritsar, Ambala, Chandigarh, Lucknow, and Patna has been sourced from the weather stations of Indian Meteorological Department (IMD) located at the airportsin each city.
Key highlights of the analysis
Annual average level of PM2.5 not lower in many cities this year despite the lockdown — while several bigger cities have witnessed a reduction, many smaller towns and cities have experienced an increase:The 2020 average PM2.5 level in many cities in upper IGP has climbed up to breach the average concentration recorded in 2019. Fatehabad in northern Haryana is the worst performer with a 35 per cent increase from 2019 level. It is followed by increases in Bhatinda(14 per cent), Agra (9 per cent), Khanna (7 per cent),MandiGobindgarh(6 per cent), Moradabad(5.5 per cent)and Kurukshetra(1 per cent). Jalandhar registered a less than 1 per cent change.
Most improvement has been noted in Sirsa which is closing 2020 with a 44 per cent lower PM2.5. Varanasi with 31 per cent, Gaya with 27 per cent,Muzaffarpurwith 15 per cent and Hisarwith 12 per cent are the other top performers in the pool. Rest of the cities show improvement in the range of 4-12 per cent. For context, Delhi’s 2020 average is 13 per cent lower than its 2019 level.
Bad November indicates influence of stubble burning:Fatehabad (the worst performer) and Sirsa (the best performer) are neighboring towns — just 40 km apart. Says Somvanshi: “Therefore, this massive variation cannot be attributed to meteorology and has to do with local factors. The annual average of these towns along with other smaller towns like Hisar and Jind in the north-west are heavily influenced by episodic pollution caused by burning of crop stubbles. The influence is so strong that it can elevate their monthly PM2.5 levels for November to that of Delhi’s, but unlike Delhi, these towns are directly exposed to the smoke. The elevated November levels do not linger on for the rest of the winter in these towns (as is the case in Delhi).”
Therefore, any change in stubble burning pattern – notes the CSE analysis — skews their annual average dramatically, which may possibly be the reason for the observed trends; further field investigation is needed to determine the real reasons.
Average level of PM2.5 has been lowestduring this summer and monsoon due to the lockdown,but this could not prevent the winter spike: The overall PM2.5 average this summer and monsoonhas been predictably lower compared to the previous year — largely because of the unprecedented economic disruption during the summer lockdown and the phased unlocking. But reopening of the economy coinciding with the onset of the winter trapped the pollution– PM2.5levels rose starting October.From the respective cleanest week the weekly average of PM2.5 in Amritsar rose 10 times, in Ambalanine times,Chandigarhsix times, Lucknow11 times, and Patna11 timesto the dirtiest week. These major cities recorded lesser deterioration than Delhi where weekly air quality worsened 14 times.
But the smaller towns have beaten the capital. Bhatinda deteriorated 23 times, Fatehabad 22 times, Muzaffarpur 19 times, Sirsa 17 times, Kanpur 16 times, and Hisar and Kaithal 15 times.
There is a marked difference between northern and eastern cities. The cities in the northrecorded their dirtiest week in the first half of November(same as Delhi-NCR); eastern cities had their dirtiest week in December.
The dirtiest week for Khanna, MandiGobindgarh, Patiala, Rupnagar, Chandigarh, Ambala, Kaithal, Kurukshetra, Yamuna Nagar, Agra, and Moradabad was the week ending November 8, 2020. For Delhi, Amritsar, Bhatinda, Jalandhar, Ludhiana, Fatehabad, Hisar, Panchkula and Sirsa the dirtiest week was the week ending November 15, 2020. Hajipur, Patna and Muzaffarpursaw their dirtiest week in the week ending December 6, 2020. Kanpur, Varanasi and Lucknowhad theirs in the week ending December 27, 2020. The dirtiest week for Gaya was the New Year’s week.
The cleanest week for Khanna, Rupnagar, Ludhiana, and Panchkula was the week ending March 29, 2020. Amritsar and Jalandhar had their cleanest week in April. Patna had its cleanest week in June and July was the cleanest for Agra, Moradabad, Patiala, Chandigarh, Ambala, Kaithal, Kurukshetra, Yamuna Nagar, Delhi and Hisar. Kanpur, Varanasi, Lucknow and Muzaffarpur had their cleanest week in the week ending August 23, 2020. MandiGobindgarh and Fatehabad had their cleanest week in the week ending August 30, 2020. Bhatinda and Sirsa had theirs in the week ending September 6, 2020. Hajipur and Gaya had their cleanest in the week ending September 27, 2020.
Average November PM2.5 levels considerably higher in the northern cities:November 2020 was dirtier across most cities in the IGP. The PM2.5 average this November was 310 per cent higher in Fatehabad, 104 per cent in Agra and 57 per cent in Kaithalcompared to November 2019. November was also same or dirtier in all Punjab and Haryana cities except Sirsawhich registered a 16 per cent cleaner month. All cities in central and eastern UP and Bihar had a 4-48 per cent cleaner November. Also, August 2020 was cleaner in all these cities compared to August 2019(except in Bhatinda, MandiGobindgarh, Patiala and Fatehabad).
Air quality gets more toxic with the onset of winter — share of tinier PM2.5 in the PM10 increases: The share of tinier and finer particles in the overall coarser PM10 concentration determines the toxicity of air. When the overall share of tinier PM2.5 in PM10 is higher, the air is more toxic as the tiny particles penetrate deep inside the lungs and cut through the blood barrier,thus increasing the health risk. Interestingly, during lockdown, when the overall suspended coarser particles had settled down reducing the PM10 levels, the PM2.5 had also come down. But its share was 33 per cent in Amritsar, 39 per cent in Chandigarh and 38 per cent in Patna – still higher than it is usually noted during summer.
But with the onset of winter, the overall levels of both have gone up, as has the percentage share of PM2.5 in overall PM10.This rose to the high 40sin October and remained high through November averaging at 55 per cent in Amritsar, 48 per cent in Chandigarh and 53 per cent in Patna. The share of PM2.5 in PM10 is generally highest on Diwali – in 2020, it reached 64 per cent in Amritsar, 69 per cent in Chandigarh, and62 per centin Patna.
Dirtier Diwali in Lucknow, but Amritsar, Ambala, Chandigarh and Patna were cleaner: The average PM2.5 level on Diwali day atTalkatora in Lucknow was 434μg/m3— up from 237μg/m3 recorded in 2019. In 2020, there was an over 100 per cent higherrise in hourly PM2.5 concentration between afternoon and night of Diwali (mostly caused due to firecracker busting). Amritsar was 7 per cent cleaner, Chandigarh 56 per cent, Ambala 57 per cent, and Patna 22 per cent. Diwali also occurred later in November in 2020 than in the previous year.
Bad air days started earlier in 2020 winter: The rolling weekly average rose over the24-hour standard or 60 μg/m3 in Amritsar on October6 (eight days earlier), Ambala on October 4 (eight days earlier), Lucknow on September 10 (29 days earlier), and Patna on October 1 (14 days earlier). Overall, the winter was dirtier all across. Chandigarh has had a relatively cleaner November with bad air setting in later this year compared to 2019.
Number of days with PM2.5 concentration meeting the standardwas considerably lower this winter — more ‘poor’ or ‘worse’ days: There have been 33 days of standard air days this winter compared to41 recorded last year in Amritsar. Similarly, standard days have been lesser by 11 days in Ambala and four in Lucknow and Patna each. In fact, in Lucknow, not a single day met the standard since the beginning of October this winter;there were 19 days of ‘severe’or ‘worse’ air quality — up from five last winter. Chandigarh bucks the trend and recorded 18 more days this winter with air quality meeting the standard.
The cyclical ups and down of pollution in the winter of 2020 has been less volatile – showing slower rise and fall than in previous winter: This inelastic behavior of PM2.5 levels in IGP citiesis in contrast to the trend seen in Delhi-NCR,where it has been more volatile during winter with frequent and quicker rise and drop.This cannot be the impact of meteorology as Delhi-NCR is exhibiting a different trend – therefore, it might be due to poor pollution control action among these cities.But more investigation is needed to understand the reasons for this.
Even with a comparatively cleaner air in 2020,mostcities recorded daily spikes similar tothose observed in 2019: CSE has compared the annual averages and peak 24-hour averagesin these cities of the IGP between 2019 and 2020. This shows thatthe smaller towns even with much lower annual average levels of PM2.5have experiencedalmost sameor higher maximum daily levels during winter when the entire region got airlocked. Punjab cities have relatively lower daily peak compared to the rest.
Need deep cuts: To avoid winter pollution peaks and the varying pattern of annual rise in pollution acrossthe Indo Gangetic Plain,the country and the region will require regional-scale action to reduce regional influences on local air pollution, as well as deep local cuts.
Says Roychowdhury: “It is clear that the region has to take forward its wins so far and raise the level of ambition to drive action across all key sectors of pollution and in the entire region. Enforce power plant standards across the state, minimise use of coal and other dirt fuels in the industry while improving emissions control, scale up public transport and vehicle restraint measures and manage waste to have a zero waste and zero landfill strategy.”
(By Pratyusha Mukherjee)