First time in India, total lockdown was announced on 22 March 2020 to stop the spread of COVID-19 and the lockdown was extended for 21 days on 24 March 2020 in the first phase. During the total lockdown, most of the sources for poor air quality were stopped in India. In this paper, we present an analysis of air quality (particulate matter-PM 2.5 , Air Quality Index, and tropospheric NO 2 ) over India using ground and satellite observations. A pronounced decline in PM 2.5 and AQI (Air Quality Index) is observed over Delhi, Mumbai, Hyderabad, Kolkata, and Chennai and also a declining trend was observed in tropospheric NO 2 concentration during the lockdown period in 2020 compared with the same period in the year 2019. During the total lockdown period, the air quality has improved significantly which provides an important information to the cities’ administration to develop rules and regulations on how they can improve air quality.

中文翻译：

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COVID-19 大流行期间封锁对印度空气质量的影响

印度于 2020 年 3 月 22 日首次宣布全面封锁以阻止 COVID-19 的传播，第一阶段的封锁于 2020 年 3 月 24 日延长了 21 天。在全面封锁期间，大部分空气质量差的来源都在印度停止。在本文中，我们使用地面和卫星观测对印度的空气质量（颗粒物-PM 2.5 、空气质量指数和对流层 NO 2 ）进行了分析。在德里、孟买、海得拉巴、加尔各答和钦奈观察到 PM 2.5 和 AQI（空气质量指数）显着下降，并且在 2020 年封锁期间观察到对流层 NO 2 浓度与同期相比呈下降趋势2019 年。在整个封锁期间，