Katihar in Bihar had the highest AQI of 360 among 163 Indian cities on Monday, as per data released by the Central Pollution Control Board. Delhi's AQI stood at 354, Noida's stood at 328 and Ghaziabad's stood at 304. Begusarai (Bihar), Ballabgarh, Faridabad, Kaithal and Gurugram in Haryana and Gwalior (MP) were also among the most polluted cities on Monday.