As per data published by the Central Pollution Control Board, Ariyalur in Tamil Nadu registered the most pristine air on Sunday, characterized by an Air Quality Index (AQI) of 28. Other cities that experienced exceptionally clean air on the same day include Tiruppur (32), Puducherry (32), Maihar (35), Cuddalore (36), Palkalaiperur (36), Rishikesh (37), Mangaluru (39), Varanasi (39), Vijayapura (39), and Kalaburagi (40).