As per the Central Pollution Control Board, Karnataka's Gadag has the cleanest air in India with an air quality index of 22 on Wednesday. This is followed by Madikeri (26), Amaravati (28), Chikkaballapur (29), Hassan (31), Rajamahendravaram (31), Chamarajanagar (32), Chikkamagaluru (33), Yadgir (33) and Thrissur (36). Bihar's Siwan recorded the worst air quality today with an AQI of 420.