key: cord-0900868-ott4bigk authors: Saini, Divyanshu; Darla, Upendra R; Lataye, Dilip H; Motghare, Vidayanand M; Shingare, Ashok A title: Effect on Ambient Air Quality in Nagpur due to lockdown to contain the spread of COVID-19 pandemic in the year 2020: a case study date: 2022-05-11 journal: Sādhanā DOI: 10.1007/s12046-022-01879-2 sha: df3607e49e7e814fb648ca98056a288a16837012 doc_id: 900868 cord_uid: ott4bigk The present paper deals with the studies on the change in concentration of three standard pollutants namely, respiratory suspended particulate matter (RSPM or PM(10)), Sulphur dioxide (SO(2)) and Nitrogen dioxide (NO(2)) because of lockdown in India to prevent the spread of COVID-19 pandemic in 2020. The monthly average concentrations of the above pollutants observed at four monitoring stations in and around Nagpur city during January to December 2020 were analyzed and compared. Due to COVID-19 pandemic, there was a complete lockdown from 25th March to 31st May 2020 and phased reopening of areas outside containment zones from June 1st onwards. It is found that the average concentration of all the three pollutants at all four stations was reduced by about 50 % to 75 % due to lockdown. During lockdown, the minimum concentration of PM(10), SO(2) and NO(2) amongst all stations were found to be 40, 5 and 11 µg/m(3,) respectively, whereas the maximum concentrations were found to be 159, 20, and 50 µg/m(3,) respectively. The concentrations during lockdown were below the standards prescribed by CPCB, which were found to increase due to reopening. The Air quality index (AQI) at all four stations during lockdown was less than 50 (i.e. SATISFACTORY), whereas it increased above 100 (i.e. MODERATE) after reopening. As a result, the annual average concentration of pollutants was reduced in 2020 compared to previous years. The main standard pollutants which pollute the ambient air vigorously are carbon monoxide (CO), sulfur dioxide (SO 2 ), nitrogen dioxide (NO 2 ) and smaller particles, including lead and gasoline additive, suspended particulate matter, etc. [1] . These pollutants are generated by various human activities, industries, construction activities, cyclones, etc. [2] . As India is a developing country, various industrialization, construction and development projects are ongoing in each part of the country releasing pollutants into the atmosphere [3] . Many of the cities are under developing conditions having construction, industrial activities due to which people are attracted towards those cities. This resulted increase in population and increase the use of vehicles which causes automobile pollution [4] . Human health mostly affected by respiratory particles (i.e. PM 10 and PM 2.5 ) present in the atmosphere [5] . These particles in the atmosphere also bounded by the polycyclic aromatic compounds and have a hazardous effect on human health [6] and lead to various carcinogenic compounds [7] . These compond not only affect the atmosphere but also the hydrosphre and stratosphere [8] [9] [10] . All these particle's main source is exhaust emission from the combustion of fuel in vehicles [11] . Due to air pollution effects at least 5,00,000 premature deaths are reported each year and the percentage of this on global scale is around 4% to 8% [12] . Pollution due to emission of vehicles in Indian megacities like Delhi contribute 70%, Mumbai 52%, and Kolkata 30% [13] . Particulate matter also contains magnetic minerals, which account for 5-15% of urban atmospheric particulate matter, with iron oxides and hydroxides accounting for 10-70% of the bulk iron content. The most common magnetic mineral contained in particulate matter is *For correspondence magnetite [14] . Various meteorological parameters temperature, wind speed, humidity solar radiation also affect the air quality [15] . Different seasons throughout the year also affect the quality of ambient air and are found to be maximum in the post-monsoon and winter season [16, 17] . The whole world has been facing the crisis of novel coronavirus pandemic since November 2019. The first patient of COVID-19 was detected in Wuhan (China), [18] . With effect of this virus, WHO declared Public Health Emergency of International Concern on 30th January 2020, and a pandemic on 11th March 2020. On 30th January 2020, the first COVID-19 patient was identified in Kerala, India. On 9th of March 2020, the first case of COVID-19 was identified in Pune, Maharashtra and on 11th March 2020 in Nagpur. In this way, the COVID-19 has spread day by day all over the world. In order to break the COVID-19 chain, all countries affected by this virus have adopted lockdown. Government of India also declared a Janta curfew on Sunday, 22nd March 2020 as a trial lockdown. The complete Lockdown was started from March 25th, 2020 in all over the country, which was still in effect in the country due to second wave of CIVID-19. Government implemented the lockdown in different phases i.e. Lockdown 1 from March 25th to April 14th, 2020 (21 days), Lockdown 2: April 15th to May 3rd, 2020 (19 days), Lockdown 3: May 4th to May 17th, 2020 (14 days), Lockdown 4: May 18th to May 31st, 2020 (14 days). During these lockdown phases many people have lost their employment, the industries were closed, transportation and other activities were closed. The lockdown started affecting the economy of the country and since the number cases of COVID-19 were started reducing little bit, the government started unlocking gradually. Which was also known as the ''Mission begin again'' in phased manner. The Lockdown 5/Unlock 1: June 1st to June 30th, 2020 (30 days), Unlock 2: July 1st to July 31st, 2020 (31 days), Unlock 3: August 1st to August 31st, 2020 (31 days), Unlock 4: September 1st to September 30th, 2020 (30 days), Unlock 5: October 1st to October 31st, 2020 (31 days), Unlock 6: November 1st to November 30th, 2020 (30 days), Unlock 7: December 1st to December 31st, 2020 (31 days). There was a complete lockdown in the country from 25th March to 31st May 2020. From 1st June 2020 the government started reopening the essential services, which was known as lockdown with some relaxation or unlocking in a phased manner. Hence there were three conditions in the year 2020. The first was a normal condition from January to 25th March or 31st March. Then the second phase/ condition was a complete lockdown from April to June 2020, where all the activities, industries, vehicles and all construction activities were closed completely except few from 1st June 2020. The third condition was after lockdown from July to December 2020, where many of the activities were allowed with some rules and restrictions. The present study deals with the effect on ambient air quality in Nagpur due to lockdown to break the chain of COVID-19 pandemic in the year 2020. For the study, three conditions have been considered in the year 2020, as throughout the year, there was a normal condition in a few months and lockdown/re-opening condition in other months. Hence, these conditions are: (1) before lockdown from January to March 2020, (2) during lockdown condition from April to June 2020, and (3) re-opening condition from July to December 2020. The air pollution concentration data from four ambient air monitoring stations in Nagpur for 2020 has been collected and monthly average concentrations of SO 2 , NO 2 , and RSPM (PM 10 ) have been determined. The comparison of air pollution concentrations within these three conditions has been reported in the present study. Nagpur is a city situated in the northeastern part of Maharashtra, a state in western India. It is located at 21.15 latitude and 79.08 longitudes with GPS coordinates 21°8 0 44.881 00 N and 79°5 0 17.357 00 E. It is situated at an elevation of 319 meters above mean sea level. As per the census 2011, Nagpur has a population of 2,228,018 with a population density of 11000 people per km 2 . Around 779259 are the main workers and 2.5 lakh children living in the city here who may be affected because of the low quality of air. The city falls under the Universal Transverse Mercator (UTM) zone of 44Q with the coordinate of 301470.33, 2339479.09 by Koppen climate classification with tropical savannah climate (Aw) with dry conditions prevailing for most of the year. Low flat-topped hills, flatlands, and dark, fertile soils in the valleys of streams and rivers define the landscape in and around Nagpur. This city is initiated to become one of India's smart cities. It results in a rapid increase in industrialization and numerous infrastructures in the region. The ambient air quality on Nagpur is being monitored by Visvesvaraya National Institute of Technology (VNIT), Nagpur. There are three monitoring stations under the National Ambient Air Quality Monitoring Programme (NAMP) and one station (i.e., Civil Lines) under State Ambient Air Quality Monitoring Programme (SAMP) sponsored by Maharashtra Pollution Control Board (MPCB), Mumbai, Maharashtra, India. One monitoring station is located at the Institute of Engineers (India), North Ambazari Road, Ramdaspeth Nagpur (Station code: 287), indicated as IE(I) in residential area. The second monitoring station is located at the office of the Executive Engineer, MIDC Hingna Road, Nagpur (Station code: 288), indicated as MIDC in the industrial area. Third monitoring station is at Government Polytechnic, Mangalwari Bazar, Sadar Nagpur (Station Code: 314), indicated as GP in the commercial area. Fourth station is located at MPCB Office Premises, Civil Lines (Station Code: 711) indicated as Civil Lines in government offices area. The location of these stations is shown in figure 1 . Three standard pollutants SO 2 , NO 2 , respirable suspended particulate matter less than 10 lm (RSPM/PM 10 ) are being monitored twice a week to get at least 104 samples per year. For daily average concentration, particulate matter is sampled at the 8-hr interval and gaseous pollutants (i.e. SO 2 and NO 2 ) at a 4 h interval at all four locations. RSPM, SO 2 and NO 2 samples were collected by using respirable dust sampler (RDS) APM460 model (Manufactured by Envirotech Instruments, New Delhi (India)). The Glass Fiber Filters are used to collect RSPM, the absorbing solutions, potassium tetrachloromercurate (TCM) and NaOH plus sodium arsenate are used to absorb SO 2 and NO 2 respectively. The sampling is done at the flow rate of 1.0-1.3 m 3 /min for RSPM and 1 L/min for SO 2 and NO 2 . The gravimetric method was used for the analysis of RSPM concentration [19] . Spectrophotometer methods; West and Gaeke method is used for the analysis of SO 2 [20] and Jacobs-Hochheiser method is used for the analysis of NO 2 [21] . This index was created to evaluate air quality using a ratio or number. The air quality index is a regular monitoring index that shows the quality of air in the atmosphere of a particular city. It differentiates the effect of pollution level on human health in short period. AQI helps people to know how the local level of pollution affects on their health. AQI has been classified into different pollution levels based on the index number. All different levels of pollution and their health effects on humans are described in table 1. AQI is calculated by the following equation: The station is located at the Institution of Engineers (India), on North Ambazari Road, Near Ramdaspeth Nagpur. The sampling is done as described earlier and the monthly average concentrations of pollutants are determined. The average concentrations of all the three pollutants for the year 2020 from January to December are determined and shown in figure 2 . From the figure, it can be seen that the concentration of SO 2 before lockdown (from January to March) varies from 14 to 10 lg/m 3 , during lockdown (from April to June) varies from 5 and 6 lg/m 3 and in reopening condition (from July to December) varies from 5 to 15 lg/ m 3 . It may be noted that the average concentration of SO 2 in March is reduced to 10 lg/m 3 , as there was a Janta curfew, where there was a complete shutdown in the city on 21st March 2020 and then the complete lockdown started from 25th to 30th June 2020. The average concentration before the lockdown was 12.34 lg/m 3 , which is very high compared to the average concentration of SO 2 during lockdown 5.33 lg/m 3 . There was a reduction of about 56.76 % in the concentration of SO 2 due to lockdown. The reduction in concentration was due to the shutdown of anthropogenic activities like vehicles, construction, industries, etc. However, the reopening of a few anthropogenic activities with some restrictions started from 1st July 2020, which again started increasing the concentration of pollutants. The average concentration of SO 2 from July to December was 8.83 lg/m 3 . A percentage increase in the concentration level of SO 2 due to reopening of the anthropogenic activities was found to increase by about 65.63 % from the concentration during the complete lockdown. From figure 2, it can be seen that the concentration of NO 2 before lockdown condition varies from 30 to 41 lg/ m 3 , during lockdown varies from 12 to 14 lg/m 3 and in reopening condition (from July to December) varies from 11 to 42 lg/m 3 . It may be noted that the average concentration of NO 2 in March is reduced to 30 lg/m 3 , as there was Janta curfew, where there was a complete shutdown in the city on 21st March 2020 and then the complete lockdown started from 25th to 30th June 2020. The average concentration before the lockdown condition was 36.33 lg/m 3 , which is very high compared to the average concentration of NO 2 during the lockdown condition, which was 12.67 lg/m 3 . Therefore, there was about a 65.14 % reduction in the concentration of NO 2 due to lockdown. All the movement of vehicles, construction activities, industries etc., were closed due to lockdown. However, the reopening of a few anthropogenic activities with some restrictions started from 1st July 2020, which again started increasing the concentration of pollutants. The average concentration of NO 2 from July to December was 23.50 lg/m 3 . A percentage increase in the concentration level of NO 2 due to reopening the anthropogenic activities was found to increase by about 85.53 % from the concentration during the complete lockdown. From figure 2 , it can be seen that the concentration of RSPM before lockdown (from January to March) varies from 124 to 148 lg/m 3 , during lockdown (from April to June) varies from 66 to 80 lg/m 3 and in reopening condition (from July to December) varies from 76 to 126 lg/m 3 . The average concentration before the lockdown condition was 132.67 lg/m 3 , which is very high compared to the average concentration of RSPM during lockdown condition was 74 lg/m 3 . Therefore, there was about 44.22 % reduction in concentration of RSPM due to lockdown. Due to the lockdown, all the movement of vehicles, construction activities and industries etc., were closed. However, the reopening of a few anthropogenic activities with some restrictions started from 1st July 2020, which again started increasing the concentration of pollutants. The average concentration of RSPM from July to December was 98.67 lg/m 3 . A percentage increase in the concentration level of The station is located at office of Executive Engineer, MIDC, Hingna Raod, Nagpur. The average concentrations of all the three pollutants for the year 2020 from January to December are determined and shown in figure 3 . From the figure, it can be seen that the concentration of SO 2 before lockdown (from January to March) varies from 12 to 15 lg/m 3 , during lockdown (from April to June) varies from 5 to 6 lg/m 3 and in reopening condition (from July to December) varies from 5 to 20 lg/m 3 . It may be noted that the average concentration of SO 2 in March is reduced to 12 lg/m 3 , as there was Janta curfew, where there was a complete shutdown in the city on 21st March 2020 and then the complete lockdown started from 25th to 30th June 2020. The average concentration before the lockdown condition was 14 lg/m 3 , which is very high compared to the average concentration of SO 2 during the lockdown condition was 6 lg/m 3 . Therefore, there was about a 58.54 % reduction in the concentration of SO 2 due to lockdown. (2022) 47:98 Page 5 of 11 from July to December was 10 lg/m 3 . Therefore, a percentage increase in the concentration level of SO 2 due to reopening the anthropogenic activities was found to increase by about 76.47% from the concentration during the complete lockdown. From figure 3 , it can be seen that the concentration of NO 2 in before lockdown condition varies from 30 to 41 lg/m 3 , during lockdown varies from 34 to 40 lg/m 3 and in reopening condition (from July to December) varies from 13 to 15 lg/m 3 . It may be noted that the average concentration of NO 2 in March is reduced to 34 lg/m 3 , as there was Janta curfew. The average concentration before the lockdown condition was 39 lg/m 3 , which is very high compared to the average concentration of NO 2 during the lockdown condition (14 lg/m 3 ). There was about a 63.25% reduction in the concentration of NO 2 due to lockdown. From 1st July 2020, this again started increasing the concentration of pollutants. The average concentration of NO 2 from July to December was 26 lg/m 3 . A percentage increase in the concentration level of NO 2 due to reopening of the anthropogenic activities was found to increase by about 82.56% from the concentration during the complete lockdown. From figure 3 , it can be seen that the concentration of RSPM before lockdown (from January to March) varies from 121 to 142 lg/m 3 , during lockdown (from April to June) varies from 73 to 85 lg/m 3 and in reopening condition (from July to December) varies from 69 to 159 lg/m 3 . The average concentration before the lockdown condition was 133 lg/m 3 , which is very high compared to the average concentration of RSPM during the lockdown condition was 78 lg/m 3 . Therefore, there was about a 41.46% reduction in the concentration of RSPM due to lockdown. The average concentration of RSPM from July to December was 107 lg/ m 3 . A percentage increase in the concentration level of RSPM due to the reopening of the anthropogenic activities was found to increase by about 37.98% from the concentration during the complete lockdown. The station is located at Government Polytechnic, Mangalwari Bazar, Sadar, and Nagpur. The average concentrations of all the three pollutants for the year 2020 from January to December are determined and shown in figure 4 . From the figure, it can be seen that the concentration of SO 2 before lockdown (from January to March) varies from 11 to 17 lg/m 3 , during lockdown (from April to June) varies 5 lg/m 3 and in reopening condition (from July to December) varies from 5 to 15 lg/m 3 . It may be noted that the average concentration of SO 2 in March is reduced to 11 lg/ m 3 . The average concentration before the lockdown condition was 14 lg/m 3 , which is very high compared to the average concentration of SO 2 during the lockdown condition was 5 lg/m 3 . There was about a 63.41% reduction in the concentration of SO 2 due to lockdown. Some restrictions started from 1st July 2020, and this again started increasing concentration of pollutants. The average concentration of SO 2 from July to December was 9 lg/m 3 . A percentage increase in the concentration level of SO 2 due to reopening of the anthropogenic activities was found to increase by about 76.67% from the concentration during the complete lockdown. From figure 4 , it can be seen that the concentration of NO 2 in before lockdown condition varies from 34 to 44 lg/ m 3 , during lockdown varies from 11 to 13 lg/m 3 and in reopening condition (from July to December) varies from 12 to 40 lg/m 3 . It may be noted that the average concentration of NO 2 in March is reduced to 34 lg/m 3 . The average concentration before lockdown condition was 39 lg/m 3 , which is very high compared to the average concentration of NO 2 during the lockdown condition was 12 lg/m 3 . Therefore, there was about a 70.09 % reduction in concentration of NO 2 due to lockdown. The average concentration of NO 2 from July to December was 23 lg/ m 3 . A percentage increase in the concentration level of NO 2 due to reopening of the anthropogenic activities was found to increase by about 97.14% from the concentration during the complete lockdown. From figure 4 , it can be seen that the concentration of RSPM before the lockdown (from January to March) varies from 108 to 139 lg/m 3 , during lockdown (from April to June) varies from 65 to 80 lg/m 3 and in the reopening condition (from July to December) varies from 79 to 134 lg/m 3 . The average concentration in before the lockdown condition was 125 lg/m 3 , which is very high compared to the average concentration of RSPM during the lockdown condition was 72 lg/m 3 . Therefore, there was about 42.40 % reduction in concentration of RSPM due to the lockdown. The average concentration of RSPM from July to December was 108 lg/m 3 . A percentage increase in the concentration level of RSPM due to reopening of the anthropogenic activities was found to increase by about 49.77 % from the concentration during complete lockdown. The station is located at MPCB office Premises, Udyog Bhawan, Civil Lines, Nagpur. The average concentrations of all the three pollutants for the year 2020 from January to December are determined and shown in figure 5 . From the figure, it can be seen that the concentration of SO 2 before lockdown (from January to March) varies from 11 to 13 lg/ m 3 , during lockdown (from April to June) varies 5 lg/m 3 and in reopening condition (from July to December) varies from 5 to 14 lg/m 3 . It may be noted that the average concentration of SO 2 in March is reduced to 11 lg/m 3 . The average concentration before lockdown condition was 12 lg/m 3 , which is very high as compared to the average concentration of SO 2 during lockdown condition was 5 lg/ m 3 . Therefore, there was about 58.33 % reduction in concentration of SO 2 due to lockdown. The average concentration of SO 2 from July to December was 9 lg/m 3 . A percentage increase in the concentration level of SO 2 due to reopening of the anthropogenic activities was found to increase by about 76.67% from the concentration during the complete lockdown. From figure 5 , it can be seen that the concentration of NO 2 in before the lockdown condition varies from 33 to 40 lg/m 3 , during lockdown varies from 11 to 12 lg/m 3 and in the reopening condition (from July to December) varies from 14 to 38 lg/m 3 . It may be noted that the average concentration of NO 2 in March is reduced to 33 lg/m 3 . The average concentration before the lockdown condition was 36 lg/m 3 , which is very high as compared to the average concentration of NO 2 during lockdown condition was 12 lg/m 3 . There was about 67.89 % reduction in concentration of NO 2 due to lockdown. The average concentration of NO 2 from July to December was 25 lg/m 3 . A percentage increase in the concentration level of NO 2 due to reopening of the anthropogenic activities was found to increase by about 112.86 % from the concentration during the complete lockdown. From figure 5 , it can be seen that the concentration of RSPM before lockdown (from January to March) varies from 68 to 70 lg/m 3 , during lockdown (from April to June) varies from 40 to 47 lg/m 3 and in reopening condition (from July to December) varies from 42 to 98 lg/m 3 . The average concentration in before lockdown condition was 69 lg/m 3 , which is high compared to the average concentration of RSPM during lockdown condition was 44 lg/m 3 . There was about 37.02 % reduction in concentration of RSPM due to lockdown. The average concentration of RSPM from July to December was 68 lg/m 3 . A percentage increase in the concentration level of RSPM due to reopening of the anthropogenic activities was found to increase by about 55.34 % from the concentration during complete lockdown. Table 2 shows the average concentrations of SO 2 , NO 2 and RSPM with their standard deviations at all three locations. Air quality index at all four stations has been determined and shown in table 3 and it is graphically represented in figure 6 . From table 1 and table 3 Outdoor air pollution: Nitrogen dioxide, sulfur dioxide, and carbon monoxide health effects. The Ame Environmental and Health Impacts of Air Pollution: A Air pollution in Delhi: Its Magnitude and Effects on Health Air Pollution From Ground Transportation an Assessment of Causes , Strategies and Tactics , and Proposed Actions for the International Community Nature of air pollution, emission sources, and management in the Indian cities Characteristics of Atmospheric Particle-bound Polycyclic Aromatic Compounds over the Himalayan Middle Hills: Implications for Sources and Health Risk Assessment Temporal variability of atmospheric particulate-bound polycyclic aromatic hydrocarbons (PAHs) over central east India: sources and carcinogenic risk assessment Characterization, Behavior, and Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in the Estuary Sediments Perand polyfluoroalkyl substances in water and wastewater: A critical review of their global occurrence and distribution Health Risk Assessment and Characterization of Polycyclic Aromatic Hydrocarbon from the Hydrosphere Exhaust particles of modern gasoline vehicles: A laboratory and an on-road study Particulate Matter Is a Surprisingly Common Contributor to Disease The causes and consequences of particulate air pollution in urban india: A Synthesis of the Science Comparison of magnetic parameters of urban atmospheric particulate matter with pollution and meteorological data Influence of Temperature, Relative Humidity and Seasonal Variability on Ambient Air Quality in a Coastal Urban Area Characterization, seasonal variation, source apportionment and health risk assessment of black carbon over an urban region of East India COVID-19 lockdowns reduce the Black carbon and polycyclic aromatic hydrocarbons of the Asian atmosphere: source apportionment and health hazard evaluation Report of the WHO-China Joint Mission on Coronavirus Disease 2019 (COVID-19). WHO-China Jt. Mission Coronavirus Dis Respirable suspended particulate matter (PM 10), cyclonic flow technique IS 5182-2 2001 Methods for Measurement for air Pollution, Part 2, sulphar di oxide Methods for Measurement for air Pollution, Part 6, oxides of nitrogen The authors would like to thank the Director VNIT, Nagpur for all the support and Central Pollution Control Board (CPCB), New Delhi and Maharashtra Pollution Control Board (MPCB), Mumbai for sponsoring the projects under National Air Quality Monitoring Programme (NAMP) and State Air Quality Monitoring Programme (SAMP). Thanks to MPCB Regional Office, Nagpur for providing support. JAN 12 36 70 14 41 148 15 43 142 17 44 139 FEB 13 40 68 13 38 126 14 40 121 13 39 128 MAR 11 33 70 10 30 124 12 34 135 11 34 108 APR 5 12 47 5 14 80 6 15 85 5 13 71 MAY 5 11 40 5 12 66 6 13 75 5 11 65 JUN 5 12 44 6 12 76 5 15 73 5 11 80 JUL 6 14 46 5 11 90 5 12 91 5 12 89 AUG 5 18 56 6 15 90 5 14 94 5 14 108 SEP 6 14 42 6 14 76 6 15 69 6 13 79 OCT 10 30 79 8 20 96 9 24 109 8 19 134 NOV 12 35 86 13 39 114 15 42 121 14 40 109 DEC 14 38 98 15 42 126 20 50 159 15 40 128 due to lockdown effect and improvement in the quality of air. The present study concluded that the main pollutant which affected the quality of air in the city, is respirable suspended particulate matter (which is above the prescribed standard given by central pollution control board i.e., 100 lg/m 3 ), SO 2 and NO 2 due to various industries, construction activities, vehicle emission, etc. To contain the spread of novel Corona Virus, Government of India imposed lockdown since 25th march 2020, which was in force till December 2020 in a phased manner, and reopening of lockdown from June 1st 2020 also known as the unlocking phase. Due to the lockdown, the average concentration of pollutants during lockdown decreased drastically (5, 11 and 65 lg/m 3 for SO 2 , NO 2 and RSPM respectively) as compared to the before lockdown condition (13, 37.5 and 115 lg/m 3 for SO 2 , NO 2 and RSPM respectively). In the reopening condition, the concentration of all pollutants again increased (9.25, 24.5 and 95.5 lg/m 3 for SO 2 , NO 2 and RSPM respectively) due to various vehicular activities, construction works, etc. Percentage reduction in the concentration of pollutants during lockdown condition were 59.26%, 66.59% and 41.27% for SO 2 , NO 2 and RSPM respectively when compared to before lockdown condition. Percentage increment in reopening condition were 73.86%, 94.52% and 44.11% for SO 2 , NO 2 and RSPM respectively, compared to during lockdown condition. Air quality indices change from 101-200 to 51-100 in lockdown and again 101-200 in reopening phase, which shows the quality of air change from MODERATE to SATISFACTIRY in lockdown and SATISFACTIRY to MODERATE in reopening condition again. Comparison of annual average concentration of all pollutants with previous years shows that there was a less pollution in the year 2020 and 2021, due to the lockdown. Due to lockdown, all the anthropogenic activities and industries were closed most of the time in the year, because of first and second wave of Corona Virus. Hence, it can be concluded that the, the main reason for the increase in environmental or air pollution is anthropogenic activities, traffic and industrial activities. If the lockdown is imposed in the pollution affected area the environmental pollution to some extent can be reduced to get the CLEAN environment.Nomenclature RSPM Respirable Suspended Particulate Matter PM 10 Particulate matter particle size less than 10 lm PM 2. 5 Particulate matter particle size less than 2.5 lm