According to data released by Central Pollution Control Board, Tamil Nadu's Ariyalur witnessed the cleanest air on Sunday with an air quality index (AQI) of 28. The other cities with cleanest air on Sunday include Tiruppur (32), Puducherry (32), Maihar (35), Cuddalore (36), Palkalaiperur (36), Rishikesh (37), Mangaluru (39), Varanasi (39), Vijayapura (39) and Kalaburagi (40).