According to International Agency for Research on Cancer (IARC), PM2.5 is classified as a group 1 human carcinogen. IQAir (2023) reported that India is the third most polluted country globally, after Bangladesh and Pakistan. This study investigates the spatial and temporal variations of PM2.5 and associated health risks across India from 2019 to 2023. The studied PM2.5 levels in India consistently surpassed the National Ambient Air Quality Standards (NAAQS) of India, China, the USA, Canada, European Union (EU), and World Health Organization (WHO). Seasonal distribution of PM2.5 indicates that the highest concentration occurs in winter. Among the top twenty most polluted cities, Bihar has eight, and Uttar Pradesh has four. Among 31 studied states/Union Territories (UT), 17 (54.84%) exceeded the Indian NAAQS levels, and 31 (100%) violated the WHO guidelines. Similarly, for 271 cities, 175 (63.64%) cities exceed the Indian NAAQS, and all 271 (100%) cities violate the WHO guidelines. The significant number of days in a year exceeded the national and international threshold levels. To meet the Indian NAAQS levels, Delhi must reduce PM2.5 to 20 μg/m3, and the top nine states reduce 10 μg/m3 each from the present levels. To achieve the WHO guideline (5 μg/m3), India would need approximately 10 to 20 years with a 20 to 10% annual reduction rate. The health risk study showed that the Hazard Quotient (HQ) threshold limits (HQ < 1) significantly exceed (2 to 10 times high). The premature mortality due to PM2.5 in India is from cardiovascular disease (CVD) at 1,945,584, followed by ischemic heart disease (IHD) at 1,252,188, chronic obstructive pulmonary disease (COPD) at 725,367, and stroke at 552,974 and high health risk observed in Indo-Gangetic Plain (IGP) region. Among the total premature deaths, CVD, IHD, COPD, and stroke contributed about 43.47%, 27.97%, 16.21%, and 12.35%, respectively. IHD is the primary cause of premature deaths in India among cardiovascular diseases. This study will help the policy makers at national and regional levels and highlight the urgent need for region-specific pollution control strategies, focusing on crucial emission sources to mitigate health risks and improve air quality across India.
