According to IQAir's 2025 World Air Quality Report (latest annual data on PM2.5 levels), the top 3 most polluted countries are:
1. Pakistan (67.3 µg/m³)
2. Bangladesh (66.1 µg/m³)
3. Tajikistan (57.3 µg/m³)
India ranks 6th. Rankings use population-weighted annual averages and can differ by metric or real-time snapshots.