According to Central Pollution Control Board's list, Meghalaya's Shillong with a good air quality index of 11 witnessed the cleanest air in India on Wednesday. This is followed by Charkhi Dadri (15), Madurai (24), Puducherry (26), Pudukottai (26), Madikeri (27), Palkalaiperur (29), Cuddalore (30), Gangtok (33), Kalaburagi (33), Virudhunagar (33), Sivasagar (35), Tirumala (36) and Korba (36).