The present study focuses on the impact of early imposed lockdowns and following unlocking phases on the status of air quality in six Tier-I and nine Tier-II cities of India as compared to the pre-lockdown measures. Furthermore, the study highlights the possible correlation of air quality index (AQI) with the initial trend of COVID-19 issues including the vaccination cases. Based on the statistical data analysis, we observed that the long-term averages for representing the short-term pre-lockdown conditions can impose a healing effect to the observed anomalies in air pollution data. However, the reduction in air pollution during the imposed lockdown series was only a phenomenal consequence, and the trends started reversing during the later phases of partial unlocking, where the correlation showed reversing trends. Being a yearly averaged parameter, the marginal reductions in the exceedance factor (EF) alone could not dictate air quality compared to the AQI. As there is incoherent variability in the pollutant distributions among the cities during various phases of the study, the trend analysis served as a preferable criterion to choose the preferred sources of variations. Based on the results, the correlation analysis revealed that air quality expressed in terms of AQI can act as an important precursor to estimate the critical phase of COVID-19 spread and the effectiveness of various control measures taken during each phase. Based on our proposed ranking, Kolkata and Patna are ranked first in the Tier-I and Tier-II cities respectively according to their responsiveness to the various institutionalized restrictions in terms of air quality parameters.

本研究的重点是与封锁前措施相比，早期实施的封锁和随后的解锁阶段对印度六个一级和九个二级城市的空气质量状况的影响。此外，该研究强调了空气质量指数 (AQI) 与包括疫苗接种病例在内的 COVID-19 问题的初始趋势可能存在相关性。基于统计数据分析，我们观察到代表短期封锁前条件的长期平均值可以对空气污染数据中观察到的异常现象产生治愈作用。然而，在强制封锁系列期间空气污染的减少只是一个显着的结果，并且在部分解锁的后期阶段趋势开始逆转，其中相关性显示出逆转趋势。作为年平均参数，与 AQI 相比，仅超标因子 (EF) 的边际减少并不能决定空气质量。由于在研究的各个阶段，城市之间的污染物分布存在不一致的变化，因此趋势分析可作为选择首选变化来源的优选标准。根据结果​​，相关分析表明，以 AQI 表示的空气质量可以作为重要的前兆来估计 COVID-19 传播的关键阶段以及在每个阶段采取的各种控制措施的有效性。根据我们提出的排名，加尔各答和巴特那在空气质量参数方面对各种制度化限制的反应程度分别在一线和二线城市中排名第一。