Introduction: Many urban cities in India, including National Capital Territory (NCT) of Delhi, have been adversely affected by air pollution since 2010s. Factors like atmospheric circulation, topography, local weather patterns, vehicular emission, industrial activities, waste burning etc. lead to extreme air pollution which is a growing threat to public health. Materials and methods: The study was conducted to examine severity of air quality in Delhi from 2015 to 2020. For this purpose, Particulate Matters (PM2.5 and PM10) measurements were done at ITO, Mandir Marg, Punjabi Bagh, Anand Vihar, and R K Puram for a period of 2015 to 2020. Everyday data was collected to interpret and analyze the trend of air pollution both seasonally and annually. Results: There was a significant increase in particulate matter levels at ITO, Mandir Marg, and RK Puram in the year 2016 while in the case of Anand Vihar the highest levels were measured in 2017. Also, Punjabi Bagh showed the highest PM10 levels in 2017. The annual average data for all five sites indicates that PM2.5 and PM10 levels were above the air quality standard throughout the study period. Anand Vihar showed the highest level of particulate matter among all five locations during the study period of 2015 to 2020. The change in seasons is also one of the important factors affecting air quality. Overall, PM2.5 and PM10 concentration were recorded maximum during winters i.e. 218.07 μg/m3 and 358.80 μg/m3 respectively. Conclusion: The results conclude that air quality deteriorated more during winters>autumn>summers>monsoon. Also, the air quality index (AQI) recorded for Delhi during the study period was highest in 2016, respectively. Though AQI decreased over the years, it lied in poor quality only