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Air pollution has emerged as a leading global health risk in recent decades, where its health impacts are primarily focused on urban areas. In India, semi-urban and rural areas are also emerging as air pollution hotspots. As these regions are out of focus, the current study monitored air pollution (PM2.5) at a rural district of Punjab in North India and attempted to study the associated health impacts. Hospital data of outpatient department (OPD), inpatient department (IPD) and all-cause mortality was correlated with change in PM2.5 concentrations. PM2.5 concentrations showed seasonal variations having relatively higher concentrations during post-monsoon and winter seasons. This rise in air pollution (annual average 92 µg/m3) was found to be mainly due to crop residue burning, including local meteorology. In comparison, hospital data shows that hospital visits and admissions were higher during monsoon. This shows that hospital admissions could not be directly linked to air pollution in rural areas as other factors such as short days during winters and self-medication, socio-economic factors and dependency on local unauthorised traditional healers may influence. The application of the AirQ + model for short-term health effects reveals that out of 2582 total deaths, preventable deaths ranging from 246 (WHO guidelines value – 10 µg/m3) to 159 (Indian NAAQS – 40 µg/m3) could be ascribed to air pollution exposure and specifically PM2.5. However, these deaths are avoidable by developing strategies to minimise air pollution in rural areas. Hence, a comprehensive approach is needed to plan air pollution reduction strategies, including urban, semi-urban and rural areas. [ABSTRACT FROM AUTHOR]

In India, Indo-Gangetic Plains (IGP) is becoming the hotspot of air pollution due to increasing anthropogenic activities such as rapid industrial growth, infrastructure development, transportation activities, and seasonal practice of crop residue burning. In the current study, seasonal variation in ambient air quality for 14 parameters, i.e., particulate matter (PM), trace gases, and volatile organic compounds (VOCs), along with meteorological parameters, was studied in 21 districts of the Haryana state for year 2019, situated in IGP. To analyze spatial variation of pollutants, ambient air quality data of 23 continuous ambient air quality monitoring stations were divided into three zones based on ecology and cropping pattern. All the zones showed annual mean PM10 and PM2.5 concentrations much higher than national ambient air quality standards. Annual mean PM10 concentration (±standard deviation) in Zones-1, 2, and 3 was 156±86, 174±93, and 143±74 μg m−3, whereas for PM2.5 was 71±44, 85±54, and 78±47 μg m−3. The results showed a considerable seasonal variation in the concentration of all pollutants. Most of the pollutants peak in the post-monsoon season, followed by winters in which crop residue burning predominates in many parts of the Haryana. PM10 concentrations increased by 65–112% and PM2.5 concentrations increased by 131–147% in the post-monsoon season compared to monsoons. The post-monsoon season showed the highest concentration of PM10, NO, and toluene (Zone-1); and PM2.5, NH3, CO, and benzene (Zone-2); whereas in winters, SO2 (Zone-1); ethylbenzene, m,p-xylene, and xylene (Zone-2); and NO2 and NOx (Zone-3) showed the maximum pollution levels. The O3 concentration was highest in the pre-monsoon season (Zone-1). The satellite-based fire counts and PCA results show a significant influence of crop residue burning in the post-monsoon season and solid biomass burning in winters on Haryana's air quality. The study could help to understand seasonal variation in ambient air quality and the influence of factors such as crop residue burning in the IGP region, which could help to formulate season-specific control measures to improve regional air quality. [ABSTRACT FROM AUTHOR]

The seasonal burning of crop residue significantly affects the environment, leading to poor air quality over Indo-Gangetic Plain (IGP) in India. Hence, there have been significant efforts to minimize crop residue burning through policy, innovations, and awareness measures. However, an abrupt increase in paddy residue burning was observed over IGP during 2020. Hence, the study explores the factors leading to this sharp rise. The business as usual trends analysis revealed that paddy crop residue burning activities increased significantly (60%) in 2020 compared to the previous year. The massive increase in crop residue burning consequently seems to be linked with the COVID-19 pandemic, which affected the farmer's income, including the poor compliance by the regulatory authorities. The study also highlights the issues and prospects for sustainable crop residue management and explores the solutions to minimize crop residue burning. There are few crops in India that have guaranteed minimum sale price and are also subsidized. These provisions encourage farmers to grow those particular crops, resulting in the generation of large amounts of crop residue from these specific crops. There have been several efforts by the Indian government, including based on recent court intervention. Still, there is no respite from burning activities and the occurrence of Delhi winter smog every year. Hence, the study emphasizes a need to adopt integrated approaches having in situ eco-friendly solutions, which enhances the farmer's income and focuses on employability, capacity building, awareness generation, and in situ economically viable solutions. [ABSTRACT FROM AUTHOR]

We have estimated the spatial changes in NO 2 levels over different regions of India during the COVID-19 lockdown (25 March–3 May 2020) using the satellite-based tropospheric column NO 2 observed by the Ozone Monitoring Instrument (OMI) and the Tropospheric Monitoring Instrument (TROPOMI), as well as surface NO 2 concentrations obtained from the Central Pollution Control Board (CPCB) monitoring network. A substantial reduction in NO 2 levels was observed across India during the lockdown compared to the same period during previous business-as-usual years, except for some regions that were influenced by anomalous fires in 2020. The reduction (negative change) over the urban agglomerations was substantial (∼ 20 %–40 %) and directly proportional to the urban size and population density. Rural regions across India also experienced lower NO 2 values by ∼ 15 %–25 %. Localised enhancements in NO 2 associated with isolated emission increase scattered across India were also detected. Observed percentage changes in satellite and surface observations were consistent across most regions and cities, but the surface observations were subject to larger variability depending on their proximity to the local emission sources. Observations also indicate NO 2 enhancements of up to ∼ 25 % during the lockdown associated with fire emissions over the north-east of India and some parts of the central regions. In addition, the cities located near the large fire emission sources show much smaller NO 2 reduction than other urban areas as the decrease at the surface was masked by enhancement in NO 2 due to the transport of the fire emissions. [ABSTRACT FROM AUTHOR]

Abstract Population growth will lead to an increase in food demand, which will exert pressure on crop production and likely increase the agricultural crop residue. The present study estimates atmospheric emissions of various pollutants from crop residue burning using the Intergovernmental Panel on Climate Change guidelines. In India 488 Mt of total crop residue was generated during 2017, and about 24% of it was burnt in agricultural fields. This resulted in emissions of 824 Gg of Particulate Matter (PM 2.5), 58 Gg of Elemental Carbon (EC) and 239 Gg of Organic Carbon (OC). Additionally, 211 Tg of CO 2 equivalent greenhouse gases (CO 2 , CH 4 , N 2 O) were also added to the atmosphere. However, crop residue can also be used for energy production in biomass power plants and has the potential of 120 TWh of electricity generation. This accounts for 10% of the total energy production of India. Trend analysis in a Business As Usual (BAU) model shows that crop residue burning emissions will increase by 45% in 2050 having 2017 as the base year. The study also examines the various sustainable approaches and proposes an integrated crop residue management model to minimize the adverse impact of agricultural waste burning on human health and the environment. Graphical abstract Image 1 Highlights • Open burning of crop residue affects the local/regional air quality and human health. • Burning of crop residue emit 211 Tg/yr of GHGs in India. • BAU scenario shows that crop residue emission will increase by 45% in 2050. • Waste crop residue can be utilized to meet 10% of the current energy production in India. • Study proposes an integrated model for sustainable crop residue management. [ABSTRACT FROM AUTHOR]

The variation in ambient air quality during COVID-19 lockdown was studied in Chandigarh, located in the Indo-Gangetic plain of India. Total 14 air pollutants, including particulate matter (PM 10 , PM 2.5), trace gases (NO 2 , NO, NO x , SO 2 , O 3 , NH 3 , CO) and VOC's (benzene, toluene, o-xylene, m,p-xylene, ethylbenzene) were examined along with meteorological parameters. The study duration was divided into four parts, i.e., a) 21 days of before lockdown b) 21 days of the first phase of lockdown c) 19 days of the second phase of lockdown d) 14 days of the third phase of lockdown. The results showed significant reductions during the first and second phases for all pollutants. However, concentrations increased during the third phase. The concentrations of SO 2 , O 3, and m,p-xylene kept on increasing throughout the study period, except for benzene, which continuously decreased. The percentage decrease in the concentrations during consecutive periods of lockdown were 28.8%, 23.4% and 1.1% for PM 2.5 and 36.8%, 22.8% and 2.4% for PM 10 respectively. The Principal Component Analysis (PCA) and characteristic ratios identified vehicular pollution as a primary source during different phases of lockdown. During the lockdown, residential sources showed a significant adverse impact on the air quality of the city. Regional atmospheric transfer of pollutants from coal-burning and stubble burning were identified as secondary sources of air pollution. The findings of the study offer the potential to plan air pollution reduction strategies in the extreme pollution episodes such as during crop residue burning period over Indo-Gangetic plain. Image 1 • Studied impact of COVID-19 lockdown phases on 14 air quality parameters. • Reduction in pollutants found to be associated with meteorology and emissions. • Increase in O 3 concentration was linked with atmospheric reactivity. • Key emission sources identified were vehicles, stubble burning, and coal power plants. • VOCs variations shows association with regional emissions e.g., solid biomass burning. [ABSTRACT FROM AUTHOR]

Near real-time monitoring of major air pollutants, i.e., particulate matter (PM 10 , PM 2.5 , PM 1 ), trace gases (O 3 , CO, NO, NO 2 , NO x , NH 3 , CO 2 , SO 2 ) and Volatile Organic Compounds (VOCs: benzene, ethylbenzene, m-, p-xylene, o-xylene and toluene) along with climatological parameters was done in eight-cities field campaigns during the rabi (wheat) crop residue burning period in the northwest of Indo-Gangetic Plain (IGP) region. The phase-wise monitoring was done at eight locations representing rural, semi-urban and urban backgrounds. During the whole campaign, the semi-urban site (Sirsa) observed the highest average concentration of PM 10 (226 ± 111 μg m -3 ) and PM 2.5 (91 ± 67 μg m -3 ). The urban site (Chandigarh) reported the minimum concentrations of all the three size fractions of particulate matter with PM 10 as 89 ± 54 μg m -3 , PM 2.5 as 42 ± 22 μg m -3 and PM 1 as 20 ± 13 μg m -3 where the monitoring was done in the early phase of the campaign. The highest VOC concentration was recorded at the semi-urban (Sirsa) site, whereas the lowest was at a rural location (Fatehgarh Sahib). NH 3 concentration was observed highest in rural sites (31.7 ± 29.8 ppbv), which can be due to the application of fertilizers in agricultural activities. Visible Infrared Imaging Radiometer Suite (VIIRS) based fire and thermal anomalies, along with HYSPLIT back trajectory analysis, show that major air masses over monitoring sites (22 %-70 %) were from the rabi crop residue burning regions. The characteristic ratios and Principal component analysis (PCA) results show that diverse sources, i.e., emissions from crop residue burning, solid biomass fuels, vehicles and industries, majorly degrade the regional air quality. This multi-city study observed that semi-urban regions have the most compromised air quality during the rabi crop residue burning and need attention to address the air quality issues in the IGP region., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Air pollution affects not only the air quality in megacities but also in medium and small-sized cities due to rapid urbanization, industrialization, and other anthropogenic activities. From October 28, 2015 to November 3, 2015, the Indo-Gangetic Plains region, including Chandigarh encountered an episode of poor visibility during the daytime. The daily average PM 2.5 concentration reached 191 μg/m 3, and visibility reduced by ∼2.2 times in the Chandigarh region. PM 2.5 concentration was found around 4 times higher than a non-haze day and more than 3 times higher than National Ambient Air Quality Standards for 24 h. A significant correlation between PM 2.5 and CO (r: 0.87) during the haze period indicated similarity in their emission sources; which was attributed to the burning of solid organic matter. Further, satellite data and back-trajectory analysis of air masses showed large-scale rice stubble burning in the agricultural fields, adjoining to the city areas. The transboundary movement of air masses below 500 m and meteorological conditions played a major role in building the pollution load in the Chandigarh region. Moreover, the enhanced concentration of biomass burning tracers, i.e., organic carbon (∼3.8 times) and K + ions (2∼ times) in PM 2.5 and acetonitrile (∼2.3 times) in ambient air was observed during the haze event. The study demonstrates how regional emissions and meteorological conditions can affect the air quality in a city; which can be useful for proper planning and mitigation policies to minimize high air pollution episodes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The impact of restrictions during various phases of COVID-19 lockdown on daily mean PM 2.5 concentration in five Indian megacities (New Delhi, Chennai, Kolkata, Mumbai, and Hyderabad) was studied. The impact was studied for pre-lockdown (1st Mar-24th Mar 2020), lockdown (25th Mar-31st May 2020), and unlocking (1st Jun-31st Aug 2020) phases. The lockdown period comprises 4 lockdown phases with distinct measures, whereas the unlocking period had 3 phases. PM 2.5 concentration reduced significantly in all megacities and met the national standards during the lockdown period. The maximum reduction in PM 2.5 level was observed in Kolkata (62%), followed by Mumbai (49%), Chennai (34%), and New Delhi (26%) during the lockdown period. Comparatively, Hyderabad exhibited a smaller reduction in PM 2.5 concentration, i.e., 10%. The average PM 2.5 levels during the lockdown in the peak hour (i.e., 07:00-11:00 h) in New Delhi, Chennai, Kolkata, Mumbai, and Hyderabad decreased by 21.3%, 48.5%, 63.4%, 56.4%, and 23.8%, respectively, compared to those before lockdown period. During the unlocking period, except for Chennai, all megacities showed a reduction in average PM 2.5 levels compared to concentrations in the lockdown period, but these reductions were mainly linked with monsoon rains in India. The current study provided an opportunity to study air pollution in the absence of major anthropogenic activities and during limited activities in monsoon season having an ecological design. The study reports a new baseline of PM 2.5 , except for monsoon, and explores this knowledge to plan future air pollution reduction strategies. The study also discusses how this new learning of knowledge could strengthen air pollution control policies for better air quality and sustainability.Graphical abstract.

Emissions from the crop residue burning adversely affect the regional and global air quality including public health. In this study, a district-wise comprehensive emission inventory of key pollutants (PM 2.5 , PM 10 , CO, CO 2 , SO 2 , NOx, N 2 O, NH 3 , CH 4 , NMVOC, EC, OC, PAH) emitted during primary crop residue burning was developed using activity data for the major agrarian states of north India for the agricultural year 2017-18. The emissions were scaled to the spatial resolution of 1 km grid to study the spatial distribution of crop residue burning activities using VIIRS Thermal anomalies datasets. An estimated 20.3 Mt and 9.6 Mt of crop residue were burned in Punjab and Haryana, resulting in an emission of 137.2 Gg and 56.9 Gg of PM 2.5 and 163.7 Gg and 72.1 of PM 10 Gg for respective states. The emissions of EC, OC, and PAHs were 8.6 Gg, 45.7 Gg, and 0.08 Gg in Punjab, whereas in Haryana emissions were 3.7 Gg, 17.7 Gg, and 0.03 Gg, respectively. The results show that rice and wheat crops were major contributor to residue burnt at the field (>90%) leading to the high load of atmospheric emissions in the IGP region. Further, CO 2 equivalent greenhouse gas emissions were 34.8 Tg and 17.3 Tg for Punjab and Haryana, respectively. Around 30000 and 8500 active fires were detected by VIIRS over the agricultural area of Punjab and Haryana during the studied year. The GIS-based bottom-up approach using gridded emission inventory shows pollutant distribution dominates over the south-western part of Punjab and north-western region of Haryana. The proximity of these regions to Delhi and transboundary movement of emissions towards Indo-Gangetic plains causes high air pollution episodes. The high-resolution inventory of various pollutants will be useful for regional air quality models to better predict and manage the hotspot of air pollution., Competing Interests: Declaration of competing interest Authors confirm that there’s no financial/personal interest or belief that could affect the objectivity. All authors read the paper and approved it., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The major objective of the current study is to estimate the groundwater quality and identify the likely sources of contamination in Chandigarh, India. Total 80 groundwater samples were collected from different locations and at various depths. Further, physcio-chemical analysis was done to estimate pH, electrical conductivity (EC), total dissolved solids, total hardness (TH), total alkalinity (TA), Na + , K + , Cl - , SO 4 2- , PO 4 3- and NO 3 - . The groundwater samples collected from shallow water sources contain higher concentration of total dissolved salts. EC, TA, Cl - , TH, Na + , and K + were found relatively higher in the shallow aquifer (<150 ft). Based on the location of pollution sources at the surface and consecutive geo-statistical distribution of physicochemical characteristics, this study suggests that non-scientific disposal of municipal solid waste, dumping of industrial waste and agricultural activities, in the nearby areas lead to the deterioration of groundwater of shallow aquifer. These observations were also confirmed using various water quality indices and outcomes of multivariate modeling, including principal component analysis. Health risk assessment for nitrates indicated that 29 groundwater samples pose non-carcinogenic health risk for children due to dermal and oral exposure. Hence, there is a need to establish a system for regularly assessing the groundwater quality to minimize public health risks., (Copyright © 2019 Elsevier Ltd. All rights reserved.)