Leveraging the COVID-19 India-wide lockdown situation, the present study attempts to quantify the reduction in the ambient fine particulate matter concentrations during the lockdown (compared with that of the pre-lockdown period), owing to the highly reduced specific anthropogenic activities and thereby pollutant emissions. The study was conducted over Bengaluru (India), using PM_2.5 (mass concentration of particulate matter having size less than or equal to 2.5 µm) and Black Carbon mass concentration (BC) data. Open-access datasets from pollution control board (PCB) were also utilised to understand the spatial variability and region-specific reduction in PM_2.5 across the city. The highest percentage reduction was observed in BC_ff (black carbon attributable to fossil fuel combustion), followed by total BC and PM_2.5. No decrease in BC_bb (black carbon attributable to wood/biomass burning) was observed, suggesting unaltered wood-based cooking activities and biomass-burning (local/regional) throughout the study period. Results support the general understanding of multi-source (natural and anthropogenic) nature of PM_2.5 in contrast to limited-source (combustion based) nature of BC. The diurnal amplitudes in BC and BC_ff were reduced, while they remained almost the same for PM_2.5 and BC_bb. Analysis of PCB data reveal the highest reduction in PM_2.5 in an industrial cluster area. The current lockdown situation acted as a natural model to understand the role of a few major anthropogenic activities (viz., traffic, construction, industries related to non-essential goods, etc.) in enhancing the background fine particulate matter levels. Contemporary studies reporting reduction in surface fine particulate matter and satellite retrieved columnar Aerosol Optical Depth (AOD) during COVID-19 lockdown period are discussed.

利用 COVID-19 印度范围内的封锁情况，本研究试图量化封锁期间环境细颗粒物浓度的减少（与封锁前相比），这是由于特定的人为活动大大减少和从而污染物排放。该研究在班加罗尔（印度）进行，使用 PM _2.5（粒径小于或等于 2.5 µm 的颗粒物的质量浓度）和黑碳质量浓度 (BC) 数据。来自污染控制委员会 (PCB) 的开放访问数据集也被用于了解整个城市PM _{2.5的空间变异性和特定区域的减少。在 BC ff}中观察到的减少百分比最高（归因于化石燃料燃烧的黑碳），其次是总 BC 和 PM _2.5。未观察到 BC _bb（归因于木材/生物质燃烧的黑碳）的减少，表明在整个研究期间未改变的基于木材的烹饪活动和生物质燃烧（本地/区域）。_{结果支持对 PM 2.5}的多源（自然和人为）性质的一般理解，与 BC 的有限源（基于燃烧）性质形成对比。_{BC 和 BC ff}的昼夜振幅有所减小，而 PM _2.5和 BC _bb的昼夜振幅几乎保持不变。_{PCB 数据分析显示 PM 2.5}的降幅最大在产业集群区。目前的封锁情况是一个自然模型，可以用来理解一些主要的人为活动（即交通、建筑、与非必需品相关的行业等）在提高背景细颗粒物水平方面的作用。讨论了 COVID-19 锁定期间表面细颗粒物减少和卫星检索柱状气溶胶光学深度 (AOD) 减少的当代研究。