Pal Subodh Chandra, Chowdhuri Indrajit, Saha Asish, Ghosh Manoranjan, Roy Paramita, Das Biswajit, Chakrabortty Rabin, Shit Manisa
Department of Geography, The University of Burdwan, Bardhaman, 713104, West Bengal, India.
Center for Rural Development and Innovative Sustainable Technology, Indian Institute of Technology Kharagpur, West Bengal, 721302, India.
Geosci Front. 2022 Nov;13(6):101368. doi: 10.1016/j.gsf.2022.101368. Epub 2022 Feb 9.
COVID-19 pandemic has forced to lockdown entire India starting from 24th March 2020 to 14th April 2020 (first phase), extended up to 3rd May 2020 (second phase), and further extended up to 17th May 2020 (third phase) with limited relaxation in non-hotspot areas. This strict lockdown has severely curtailed human activity across India. Here, aerosol concentrations of particular matters (PM) i.e., PM, PM, carbon monoxide (CO), nitrogen dioxide (NO), sulphur dioxide (SO), ammonia (NH) and ozone (O), and associated temperature fluctuation in four megacities (Delhi, Mumbai, Kolkata, and Chennai) from different regions of India were investigated. In this pandemic period, air temperature of Delhi, Kolkata, Mumbai and Chennai has decreased about 3 °C, 2.5 °C, 2 °C and 2 °C respectively. Compared to previous years and pre-lockdown period, air pollutants level and aerosol concentration (-41.91%, -37.13%, -54.94% and -46.79% respectively for Delhi, Mumbai, Kolkata and Chennai) in these four megacities has improved drastically during this lockdown period. Emission of PM has experienced the highest decrease in these megacities, which directly shows the positive impact of restricted vehicular movement. Restricted emissions produce encouraging results in terms of urban air quality and temperature, which may encourage policymakers to consider it in terms of environmental sustainability.
2019年冠状病毒病疫情迫使印度从2020年3月24日至2020年4月14日（第一阶段）实施全国封锁，后延长至2020年5月3日（第二阶段），并进一步延长至2020年5月17日（第三阶段），非热点地区仅有限度放宽限制。这种严格的封锁严重限制了印度各地的人类活动。在此，对印度不同地区四个特大城市（德里、孟买、加尔各答和钦奈）的特定物质（PM）即细颗粒物（PM）、可吸入颗粒物（PM）、一氧化碳（CO）、二氧化氮（NO）、二氧化硫（SO）、氨（NH）和臭氧（O）的气溶胶浓度以及相关温度波动进行了调查。在疫情期间，德里、加尔各答、孟买和钦奈的气温分别下降了约3℃、2.5℃、2℃和2℃。与前几年和封锁前时期相比，这四个特大城市的空气污染物水平和气溶胶浓度（德里、孟买、加尔各答和钦奈分别下降了-41.91%、-37.13%、-54.94%和-46.79%）在封锁期间大幅改善。细颗粒物（PM）的排放量在这些特大城市中下降幅度最大，这直接显示了限制车辆流动的积极影响。受限排放物在城市空气质量和温度方面产生了令人鼓舞的结果，这可能会促使政策制定者从环境可持续性的角度加以考虑。
