This study aimed to comprehensively analyze the Air Quality Index (AQI) trajectory across six diverse locations in Himachal Pradesh, India, by identifying primary pollutants. The investigation revealed PM10 as the predominant pollutant in these regions. To assess AQI trends, both the Mann-Kendall test and Sen’s Slope were employed. The findings unveiled a consistent upward trend in Baddi, known as an industrial hub, indicating worsening air quality over the study period. In contrast, Poanta Sahib and Kala Amb showed a declining trend in AQI, suggesting potential improvements in air quality over the span of 12 months. However, the AQI fluctuations in Shimla, Parwanoo, and Damtal were characterized by a mixed trend, indicating varying patterns and potential factors influencing air quality in these locations

Air Quality Index, Mann-Kendall test, Sen’s Slope, National Air Quality Monitoring Program

The results of the study showed that there were various trends among sites under investigation. Baddi, an industrial hub, showed a consistent upward trend in AQI; hence it indicated worsening air quality as time went on. In contrast, Poanta Sahib and Kala Amb demonstrated declining trends in AQI suggesting possible improvements in air quality over a 12 month-period. However, Shimla, Parwanoo and Damtal presented mixed trends thus signifying varying patterns and likely factors affecting air quality. Most importantly, Baddi, Kala Amb and Ponta consistently revealed winter (October to May) and summer values for AQI above 100 implying poor air quality while showing figures below 50 but above 100 ranging between July and September which implied good air quality. Damtal, Parwanoo and Shimla had good air quality round the year whereby their AQIs stood at between 50-100 throughout the year. The least polluted area is Shimla among all other locations assessed herein. Furthermore, maximum operator method used to calculate overall AQI has been observed to contain certain limitations since it only relies on a single pollutant. Therefore, this wide-ranging analysis emphasizes the significance of continued monitoring as well as assessment regarding observable tendencies involving atmospheric conditions meant to facilitate ecological governance together with policy development in Himachal Pradesh

Amruth Bhargav, Arun Kumar, Banti Kumar, Sachin Kumar and Rajesh Thakur (2025). Assessment of Air Quality Trends in Himachal Pradesh: A Comparative Analysis of Six Locations. Biological Forum, 17(5a): 52-58.